Rival Libyan militia clashed at Tripoli's international airport on Monday after an armed Libyan brigade surrounded the airport and forced it to close, a Reuters witness said.

Gunfire could be heard at the airport, a Reuters reporter at the scene said, adding he could see men entering the airport carrying rocket-propelled grenades.

Earlier gunmen from the al-Awfea brigade surrounded the airport to secure the release of one of their leaders whom they believed had been kidnapped and held there, a security official said.