The United Nations ended its 10-year peacekeeping mission in Mali on Monday following the government’s request that alleged the force was inadequate to respond to growing violent extremism in the West African nation.

“The Malian terrain was vast and difficult,” the commander of the 13,000-strong force, Maj. Gen. Mamadou Gaye, told the closing ceremony in Bamako, the capital.

The UN effort in Mali has been the deadliest peacekeeping mission in the world, with more than 300 personnel killed.

Landlocked Mali has struggled to contain an Islamic extremist insurgency since 2012. Extremist rebels were forced from power in northern cities the following year with the help of a French-led military operation. But rebels regrouped in the desert and began launching attacks on the Malian army and its allies — which soon included the UN force.

In June, however, Mali’s junta asked the UN mission to leave, claiming that its “future outlook doesn’t seem to respond to the security needs” of the country. The French force left last year under pressure from the junta.

Gaye, the UN mission commander, expressed confidence in Mali’s security forces to resolve the security crisis.

“It’s been a very positive mission which, when all is said and done, has given us a great deal of satisfaction, even if we’d like to do more with the limited resources we have,” he said.

But many in Mali have said the peacekeeping force has brought no stability, especially in the north where rebels are fighting to expand the territories they control.

Mahamadou Bassirou Tangara, a security analyst and researcher with the Conflict Research Network West Africa, said although the peacekeepers were not successful in helping to recover lost territories, they were able to improve the capacity of Malian security forces to tackle the crisis.