A U.S. special forces mission into Libya ended in confusion and embarrassment after the Libyan Air Force posted photos of the American commandos on their Facebook page.

“Libya’s air force said 20 US soldiers arrived at Libya’s Wattiya airbase on Monday, but left soon after local commanders asked them to go because they had no permission to be at the base. It was unclear if another branch of the Libyan military had authorized the mission,” reports the UK Guardian.

A Pentagon statement portrayed the situation as follows:

With the concurrence of Libyan officials, US military personnel traveled to Libya on 14 December to engage in a dialogue with ‎representatives of the Libyan National Army. While in Libya, members of a local militia demanded that the US personnel depart. In an effort to avoid conflict, they did leave, without incident.

The situation in Libya is deadly serious, with a civil war exacerbated by the Islamic State pushing into the ruined country and driving for its oil fields.

The UK Daily Mail reports flight trackers revealed “the unit was flown back to Pantelleria airport, Sicily.”

Senior defense officials described the situation to NBC News as “a possible mix-up between the Libyan air force and army.” The officials said U.S. special forces have been “in and out of Libya” for “some time now” on advisory missions.

The Libyans proceeded to post photos of the American commandos “posing in the sunshine with Libyan soldiers,” boarding a passenger plane, and driving a dune buggy. The post said these soldiers “disembarked in combat readiness wearing bullet proof jackets, advanced weaponry, silencers, handguns, night vision devices and GPS devices.”

Generally speaking, special forces operators prefer not to advertise deployments into conflict zones with Facebook posts.

NBC noted that the Libyan air force’s Facebook post complained there were “so many questions about who is dealing with foreign armies under the cover of the army,” which would support the speculation about a breakdown in communications between branches of that country’s armed forces.

The base where all this happened, Wattiya, is close to the ISIS stronghold of Sabratha in western Libya, which the Guardian says is fueling speculation that U.S. special forces will soon be conducting combat operations against the Islamic State in Libya, although one Libyan source said they might have been in the area for training purposes.

It is also noted that Wattiya is the focus for action against the Islamist insurgents currently holding Tripoli by Libya’s internationally-recognized legitimate government, so the American troops could be playing a role as either trainers or combat forces in that conflict.