A mysterious airstrip being built on a remote island in Yemen is nearing completion, satellite photos analyzed by The Associated Press show, one of several built in a nation mired in a stalemated war threatening to reignite.

The airstrip on Abd al-Kuri Island, which rises out of the Indian Ocean near the mouth of the Gulf of Aden, could provide a key landing zone for military operations patrolling that waterway. That could be useful as commercial shipping through the Gulf and Red Sea — a key route for cargo and energy shipments heading to Europe — has halved under attacks by Yemen’s Iranian-backed Houthi rebels. The area also has seen weapons smuggling from Iran to the rebels.

The runway is likely built by the United Arab Emirates, which has long been suspected of expanding its military presence in the region and has backed a Saudi-led war against the Houthis.