MOGADISHU, Somalia (AP) — Peacekeepers plan to replace departing Ugandan troops at four bases near Somalia’s capital to prevent al-Shabab militants from exploiting a security vacuum, according to a letter from the African Union mission to the U.N. support office in Somalia obtained by The Associated Press.

Uganda says all its troops will leave Somalia by the end of 2027, ending a 20-year deployment. Those leaving now were deployed under a bilateral agreement with Somalia’s government. Uganda also contributes troops to the African Union peacekeeping mission.

Funding shortages have accelerated the withdrawal, said Farhan Isak Yusuf, deputy executive director of Somali Public Agenda, a Mogadishu-based public policy research organization. Uganda’s military statement did not say why the bilateral troops were being withdrawn immediately.

The peacekeepers will move from Barawe, a port town about 220 kilometers (135 miles) southwest of Mogadishu. It is unclear who will take over the bases they leave behind.

Uganda announced Monday that the withdrawal had begun, with the first soldiers already home. Military spokesman Col. Chris Magezi said troops deployed under the bilateral agreement would finish leaving within days. Uganda’s remaining forces, including its AU peacekeepers, would gradually withdraw by the end of 2027.

The Oct. 31 letter says Uganda deployed the bilateral force after an April 2025 summit where African leaders called for more peacekeepers to fight al-Shabab. Those Ugandan troops helped recapture and hold territory over the next 17 months.

The African Union Support and Stabilization Mission in Somalia plans to take over four of the positions — Sabid-Anole, Bariire, Awdheegle and Bulonagad — during troop rotations scheduled for November. The letter describes the locations as critical to protecting Mogadishu.

Somali army commander Maj. Gen. Ibrahim Mohamed Mohamud visited troops in Barawe on Monday, receiving briefings on local security, according to an army statement.

He instructed troops to remain on high alert and intensify operations against al-Shabab. The statement did not say whether Somali soldiers would take over the AU bases.

Somali and African Union troops captured Barawe from al-Shabab in 2014. The militants had used its port to bring in fighters and weapons and export charcoal to finance their operations.

Yusuf said the Somali army lacks resources and faces a difficult security environment. Lower Shabelle, where the Ugandan troops now withdrawing were stationed, is critical to protecting Mogadishu, he said.

Uganda’s withdrawal plans come just after the United Nations’ political mission in Somalia closed, ending more than three decades of successive missions that helped rebuild the country and mediate political disputes.

United Nations aid agencies remain in Somalia. A separate support office continues providing supplies and transport to African Union peacekeepers and some Somali security forces.

Somali authorities have portrayed the political mission’s closure as a milestone toward managing their own affairs. But it comes amid a dispute over the president’s right to remain in office and continuing militant attacks.

Last week, an officer who survived an ambush said at least 20 Somali soldiers were killed in the Bay region. The government acknowledged damage to military vehicles but disclosed no troop casualties.