DIRKOU, Niger — The C.I.A. is poised to conduct secret drone strikes against Qaeda and Islamic State insurgents from a newly expanded air base deep in the Sahara, making aggressive use of powers that were scaled back during the Obama administration and restored by President Trump.

Late in his presidency, Barack Obama sought to put the military in charge of drone attacks after a backlash arose over a series of highly visible strikes, some of which killed civilians. The move was intended, in part, to bring greater transparency to attacks that the United States often refused to acknowledge its role in.

But now the C.I.A. is broadening its drone operations, moving aircraft to northeastern Niger to hunt Islamist militants in southern Libya. The expansion adds to the agency’s limited covert missions in eastern Afghanistan for strikes in Pakistan, and in southern Saudi Arabia for attacks in Yemen.

Nigerien and American officials said the C.I.A. had been flying drones on surveillance missions for several months from a corner of a small commercial airport in Dirkou. Satellite imagery shows that the airport has grown significantly since February to include a new taxiway, walls and security posts.