The Sahel on the Brink of Interstate Conflict: Military Tensions between the AES and ECOWAS

The Sahel region is currently at a critical turning point in its security history. As jihadist groups continue their offensives, a new fracture threatens regional stability: the escalation of military tensions between the Sahel States Alliance and the Economic Community of West African States risks transforming this counter-terrorism crisis into a large-scale inter-state conflict.

The official activation of the AES joint force in December 2025, comprising approximately 5,000 soldiers from Mali, Burkina Faso, and Niger, marks a definitive break with the multilateral security architecture that prevailed until 2021. This initiative is set against a backdrop of accelerated militarization of the region, exacerbated by the announcement in August 2025 of the ambitious ECOWAS project to deploy a 260,000-strong counter-terrorism force, with an annual budget of $2.5 billion for logistics and operational support.

The roots of this security fragmentation date back to the 2023 coup in Niger. The threat of military intervention brandished by ECOWAS to restore constitutional order crossed a decisive political threshold, transforming the regional organization from intermediary to perceived adversary in the eyes of the military juntas. This posture catalyzed the formation of the AES as a mutual defense mechanism, codifying a break with the multilateral security regime that included ECOWAS, the European Union, the United States, and France.

Operation Yereko 2, conducted between February and March 2025 in the Liptako-Gourma area by the forces of the three AES states, demonstrated effective tripartite military coordination and foreshadows the operational capabilities of the new unified force. This border region remains the epicenter of activity for groups affiliated with Al-Qaeda (JNIM) and the Islamic State (ISGS), with a consolidated territorial presence in northern and central Mali for JNIM, while ISGS maintains positions in northern Burkina Faso and western Niger following inter-jihadist clashes that began in 2020.

Geopolitical tensions are crystallizing around the Nigerian military intervention in Benin in February 2026 to counter a coup attempt, hailed as a victory for ECOWAS. The emergency landing of a Nigerian C-130 in Burkina Faso two days later was interpreted by the AES as a violation of sovereignty, triggering an authorization to neutralize aircraft involved in future violations of airspace. Reports that France may have provided intelligence and surveillance support to Nigeria have fueled concerns about a French reintegration into the AES security landscape.

The U.S. airstrikes on December 25 against alleged Islamic State positions in northwestern Nigeria, described as "powerful and deadly" by President Donald Trump, are part of a strategy to legitimize the U.S. counter-terrorism role in the region. While targeting militants operating in Nigeria, these strikes pave the way for deeper security cooperation between Washington and Abuja, with potential implications for operations against ISWAP and Boko Haram in northeastern Nigeria.

This convergence of American and Nigerian interests inevitably shapes the operational capabilities of the proposed 260,000-soldier ECOWAS force. The AES states, determined to protect their sovereignty against Western security influence, perceive this configuration as a direct threat. The porosity of borders and the fluidity of combat environments multiply the risks of military confrontations between ECOWAS and AES forces, particularly in adjacent areas where both coalitions operate against the same jihadist groups.

Reported incidents of gunfire and explosions near the main airport in Niamey in February 2026, at Base Aérienne 101, illustrate the current security volatility. With U.S. strikes already having hit unintended targets, the risk that future air operations by an ECOWAS supported by Washington could spill over into AES territory cannot be ruled out. For deterrence, the AES may seek to mobilize Russian military support, evoking the security rivalry dynamics of the Cold War era.

By turning away from their traditional Western partners, the AES states have designated Russia as their main security partner, a strategic pivot aimed at counterbalancing decades of American and European influence in West Africa. This reconfiguration of alliances deepens geopolitical tensions and potentially transforms the Sahel into a new theater of rivalry between great powers, with an AES supported by Moscow on one side and an ECOWAS backed by Washington and Paris on the other.

Without reconciliation between the AES and ECOWAS, two major risks loom over peace and regional stability. First, the escalation of geopolitical tensions could lead to direct military confrontations between member states, plunging West Africa into a regional war. Such a conflict would serve the counter-terrorism objectives of neither party and create an operational space for the expansion of armed groups amid fractured and distracted security responses. Second, this confrontation risks turning West Africa into an arena of great power rivalry, where the use of the veto in the United Nations Security Council could further complicate conflict resolution.

In light of the planned deployment of 1,650 personnel from the ECOWAS Rapid Deployment Force in 2026, announced by the Commissioner for Political Affairs, Peace, and Security Abdel-Fatau Musah, the central question remains that of operational coordination with AES forces. The disproportionate scale of the 260,000-soldier force project contrasts with the financial and logistical challenges that doomed the G5 Sahel initiative, funded by the European Union, which operated between 2017 and 2023 before collapsing under the weight of internal tensions and uneven results.

ECOWAS, the most experienced regional security organization in Africa, possesses the diplomatic capacity necessary to negotiate an operational concept that ensures respect for AES sovereignty. For progress to be made, the French-speaking member states of ECOWAS should take the lead in these diplomatic efforts, while Nigeria would exercise its influence more discreetly. ECOWAS's ability to regain control of its security agenda and define the terms of external engagement will shape not only the future of West Africa but that of the continent as a whole.

The alternative to this diplomatic path is a return to a Cold War-style bloc politics in West Africa, as the region slides into chaos. The AES and ECOWAS states face a crucial choice: to revive past geopolitical rivalries or negotiate a security sub-coalition prioritizing human security alongside national sovereignty. In a context where jihadist groups control increasingly vast territories and where civilian populations bear the consequences of two decades of militarized counter-terrorism approaches, the urgency for effective regional coordination has never been more pressing.