Yemeni government officials in the southern port city of Aden say government forces are clashing with militant groups for control over the strategic Port of Aden.

The officials say the militants — who are using the port to run lucrative smuggling operations — have refused to hand over the port to the government.

A drive-by shooting on Thursday in Aden killed Ahmed al-Idrisi, a top pro-government militia leader, just hours after he reluctantly agreed to hand over control of the city's port to government troops.

Security officials claimed that al-Idrisi publicly backed the government but maintained secret deals with extremists and anti-government forces.

All officials spoke on condition of anonymity because they were not authorized to speak to reporters.