The Horn Without Borders: Sudan, the Red Sea, and a Region’s Interlocking Crises

Nexa Insight · Regional Analysis · Horn of Africa Weekly Update — Issue No. 1

Reference: NRTC/HAWU/2026-01  |  Coverage period: 12–19 August 2026  |  Published: 19 August 2026

The past week has confirmed a pattern that has defined the Horn of Africa for much of 2026: no single crisis is contained within its own borders. Sudan’s civil war continues to draw in neighbouring militias and cross-border patronage networks; the Ethiopia–Eritrea rivalry over Red Sea access is hardening into open military posturing; Somalia’s constitutional order and its war against Al-Shabaab are both under strain simultaneously; and South Sudan’s 2018 power-sharing framework is, for practical purposes, no longer functioning. Read together, these developments point to a region where the traditional distinction between “internal” and “regional” conflict has largely dissolved. This briefing sets out the week’s principal developments and their implications for decision-makers.

1. Sudan: A War Fought on Two Fronts, With Opposite Trajectories

Sudan’s civil war entered its fourth year showing a genuinely divergent picture depending on theatre. In the east, an alliance between the Rapid Support Forces (RSF) and the Sudan People’s Liberation Movement–North (SPLM-N) launched a major assault on the town of Geisan in Blue Nile state on 11 August, using artillery and drones. RSF-aligned fighters reportedly reached the town’s main market before the Sudanese Armed Forces (SAF) fell back to its principal military base in the area, and fighting was still active as of this writing (Sudan Tribune, 2026a; 2026b).

In the west, the picture is reversed. SAF and allied Joint Force units repelled two successive RSF assaults on the Bir Saliba area near el-Geneina, the RSF’s last major stronghold in West Darfur, reportedly destroying or capturing dozens of vehicles and killing a senior RSF field commander. Army-aligned forces have also cut several RSF supply routes toward the Chadian border (Al Jazeera, 2026).

For regional leaders, the analytical point is not that either side is “winning” the war outright, but that the RSF’s shift from territorial expansion to a more defensive, drone-reliant posture in the west, even as it opens new fronts with SPLM-N support in the east, suggests a paramilitary force adapting to attrition rather than approaching collapse. This has two implications: first, mediation efforts premised on an imminent military decision on either side are likely to be overtaken by events; second, the internationalisation of the war — through SPLM-N’s alignment with the RSF, and the flow of fighters and weapons across the South Sudanese and Chadian borders — means that Sudan’s neighbours have a direct stake in outcomes, whether they seek that role or not.

2. Ethiopia–Eritrea: The Red Sea Question Sharpens

Tension between Addis Ababa and Asmara, simmering since Ethiopian Prime Minister Abiy Ahmed’s September 2025 declaration that Ethiopia’s landlocked status “needed to be corrected,” continued to intensify this week. Both governments have moved additional forces toward their shared border, and Ethiopian officials have accused Eritrea of both occupying Ethiopian territory and providing support to armed groups opposed to the federal government — allegations Asmara denies (BBC News, 2026; Atlantic Council, 2026).

Compounding this, the Tigray People’s Liberation Front (TPLF) reinstated its pre-war regional council in May 2026, a move Addis Ababa regards as a unilateral breach of the 2022 Pretoria Agreement, and there have been credible reports of forced recruitment by TPLF-aligned Tigray Defence Forces. On 1 August, an armed incursion originating from Sudanese territory and attributed to TPLF-aligned elements was repulsed by the Ethiopian National Defence Force within hours — a reminder that the Pretoria settlement’s security provisions remain incompletely implemented three years on (Horn Review, 2026; Critical Threats Project, 2026).

It is worth stating plainly, in the interest of analytical neutrality, that most regional and international assessments consider a full-scale Ethiopia–Eritrea war unlikely in the near term: the economic and human costs of the 1998–2000 war remain a powerful deterrent, and outside powers, including the United States and Gulf states, have strong incentives to prevent renewed conflict. The more probable trajectory is an intensification of proxy activity — through Tigray, through Somali territory, and through Sudan — rather than a conventional interstate war. Leaders should nonetheless note that proxy escalation carries its own risk of miscalculation, particularly where multiple armed actors are operating along contested borders simultaneously.

3. Somalia: Constitutional Legitimacy Strain Meets a Resurgent Al-Shabaab

Somalia’s internal politics remain unsettled. Following constitutional amendments passed in March 2026 that extended presidential and parliamentary terms from four to five years, President Hassan Sheikh Mohamud has maintained that his mandate runs until May 2027, a position the political opposition continues to reject as unconstitutional (Somali Guardian, 2026; CNBC Africa, 2026). This week added a further data point on the state’s human rights posture: journalist Mascuud Warsame was released on 12 August after 39 days in detention by the National Intelligence and Security Agency without charge or judicial review — a case that has drawn criticism from press freedom monitors regarding due process standards (Horn Observer, 2026).

This political uncertainty coincides with a deteriorating security picture. Al-Shabaab has exploited the drawdown of African Union forces to retake territory in the Lower Shabelle and Middle Jubba regions and has sustained a campaign of bombings in Mogadishu, including a February 2026 attack near the capital’s airport that killed more than thirty people. The African Union Support and Stabilisation Mission (AUSSOM) — the successor to ATMIS — is itself now at risk after the United States announced it would end logistical support beyond December 2026, raising the prospect of a funding and capability gap precisely as the insurgency regains momentum (International Crisis Group, 2026a; U.S. Department of the Treasury, 2026).

The convergence of contested political legitimacy and a resurgent insurgency is the more consequential story here than either factor alone. Security forces cannot be expected to sustain operational tempo against Al-Shabaab while the political leadership’s legitimacy is simultaneously being contested by major opposition figures; historically, in Somalia as elsewhere, periods of elite contestation have tended to correlate with, not merely coincide with, insurgent gains.

4. South Sudan: The Quiet Collapse of Power-Sharing

The 2018 Revitalised Peace Agreement is, in practical terms, no longer operative. First Vice President Riek Machar has remained under house arrest since March, facing charges including treason and crimes against humanity, and has not appeared publicly for months, prompting expressions of concern from international monitors over his welfare. His party, the SPLM-in-Opposition, has formally declared the peace agreement defunct, and was excluded from a recent Presidency meeting at which other signatories agreed to rule out any further extension of the transitional period, with elections now scheduled for December 2026 (Radio Tamazuj, 2026; PBS NewsHour, 2026; International Crisis Group, 2026b).

Meanwhile, fighting continues in Jonglei state, which independent monitors attribute directly to the breakdown of the unity government structure established under the 2018 accord. An election held under these conditions — without the participation of the country’s principal opposition figure, amid active internal conflict, and without an inclusive process agreed by all signatories — carries an evident risk of being viewed domestically and internationally as procedurally deficient, whatever its formal legality.

5. Regional Alignments: A Cairo–Asmara–Mogadishu Axis and Addis Ababa’s Isolation

A structural trend worth flagging for leaders is the consolidation of an informal alignment between Egypt, Eritrea, and Somalia, oriented around shared concern over Ethiopian regional ambitions — whether in the form of the Grand Ethiopian Renaissance Dam, the 2024 Ethiopia–Somaliland memorandum of understanding, or Addis Ababa’s stated ambition for Red Sea access. Egypt’s delivery of military assistance to Somalia and its deepening security cooperation with Asmara are best read not as isolated bilateral moves but as components of a coordinated strategy to constrain Ethiopian influence (Horn Review, 2026b; The Conversation, 2026).

For Ethiopia, this presents a genuine strategic dilemma: engagement on Red Sea access, however framed domestically, risks reinforcing the very coalition it is intended to counter. For the wider region, the emergence of bloc-style alignments layered on top of already active conflicts in Sudan, Somalia, and South Sudan raises the stakes of any single crisis escalating, since blocs create incentives for external backing rather than local containment.

6. Maritime Corridor: Persistent Red Sea Shipping Risk

Although Houthi attacks on commercial shipping have not resumed at the intensity seen in 2024, the group’s declared blockade of Saudi ports — with strikes reportedly reaching as far as Yanbu — and its continued, if narrowed, targeting criteria mean that Red Sea and Bab-el-Mandeb shipping risk remains elevated rather than resolved (U.S. Maritime Administration, 2026; Washington Post, 2026). For Horn of Africa states whose ports (Djibouti, Berbera, Port Sudan) depend on continued confidence in the corridor, this is a standing vulnerability that compounds, rather than sits apart from, the region’s land-based conflicts.

About the Author

Abdinasir Hassan Timoweyne is Chairperson of the Nexa Research and Training Centre and a political analyst specialising in the Horn of Africa and the Middle East. He lectures in International Relations at New Generation University.

References

1. Al Jazeera (2026). Has the Sudanese army turned the page on control of western Sudan? aljazeera.com
2. Atlantic Council (2026). Ethiopia and Eritrea are on the brink of war again. atlanticcouncil.org
3. BBC News (2026). Ethiopia accuses Eritrea of preparing for war as Red Sea tensions rise.
4. CNBC Africa (2026). Somali parliament approves constitution change to extend president’s term, delay election. cnbcafrica.com
5. Critical Threats Project (2026). Ethiopia Prepares for War: Africa File Special Edition. criticalthreats.org
6. Horn Observer (2026). Latest News. hornobserver.com
7. Horn Review (2026a). Weekly Geopolitical Report, Issue No. 33. hornreview.org
8. Horn Review (2026b). Egypt’s Somalia Strategy and the Rising Pressure on Ethiopia. hornreview.org
9. International Crisis Group (2026a). New Chapter, Same Stalemate: Somalia’s War with Al-Shabaab. crisisgroup.org
10. International Crisis Group (2026b). Halting South Sudan’s Slide into War. crisisgroup.org
11. PBS NewsHour (2026). Concern grows for safety of South Sudan opposition leader facing treason and other charges. pbs.org
12. Radio Tamazuj (2026). Machar allies reject Kiir’s 2026 election plan. radiotamazuj.org
13. Somali Guardian (2026). Somalia president says term not expired as opposition rejects his legitimacy. somaliguardian.com
14. Sudan Tribune (2026a). RSF and SPLM-N launch attack on Sudan’s Geisan town. sudantribune.com
15. Sudan Tribune (2026b). RSF, allies seize parts of Geisan in Sudan’s Blue Nile state. sudantribune.com
16. The Conversation (2026). Egypt-Ethiopia hostilities are playing out in the Horn — the risk of new proxy wars is high. theconversation.com
17. U.S. Department of the Treasury (2026). Terrorist Financing Targeting Center Designates Al-Shabaab Networks in Somalia. home.treasury.gov
18. U.S. Maritime Administration (2026). Advisory 2026-006: Red Sea, Bab el-Mandeb Strait, Gulf of Aden, Arabian Sea, and Somali Basin — Houthi Attacks on Commercial Vessels. maritime.dot.gov
19. Washington Post (2026). How the Houthi militia weaponized shipping in the Red Sea. washingtonpost.com