TRIPOLI, Libya (CNN) -- Armed rebels remained at the international airport in Libya's capital and government security checkpoints sprung up around the city Monday amid high tensions over a detained militia leader.

Earlier Monday, militia forces had seized control of part of the airport in their dispute with officials over the matter.

A spokesman for the Tarhouna militia said forces were withdrawing after officials had agreed to release the detained leader -- a report that the government confirmed.

But the rebel leader had not yet been released, and militia were still mobilizing around the airport.

Government vehicles armed with anti-aircraft weaponry were seen heading toward the facility.

Two platoons of the Tarhouna militia moved into the airport overnight because of an ongoing dispute with the national government, sparked by the disappearance of the militia leader on the airport road Sunday, a security source said.

The Libyan government sent emissaries to meet with the militia group Sunday night, Deputy Foreign Minister Abdul Karim Ahmed Bazama said.

At the time, the deputy foreign minister said he did not know where the militia leader was or the circumstances of his disappearance.

The atmosphere at the airport was tense, but calm.

Earlier Monday, local journalists who have worked with CNN in the past said armed militia members had escorted passengers at the airport to cars and described it as an evacuation of the terminal.

CNN's Jomana Karadsheh contributed to this report.