(Adds TV footage, details)
By Feras Bosalum and Ulf Laessing
TRIPOLI, July 13 (Reuters) - Heavy fighting broke out between rival militias near the airport of the Libyan capital Tripoli on Sunday, residents and officials said, reporting explosions and gunfire that forced the suspension of all flights.
Explosions were heard from early morning on the airport road and other parts of Tripoli. Residents said that Zintan militiamen who controlled the airport had come under fire and local TV footage suggested that the attacking rebels were from the western city of Misratis.
Libya has been in turmoil since the overthrow of Muammar Gaddafi in 2011, with the government unable to control battle-hardened militias who helped to oust Gaddafi but continue to defy state authority.
Zintan forces have controlled the airport since the Gaddafi's ousting, but rebels from both Zintanis and Misratis had been placed on the state pay roll in an unsuccessful attempt by the government to win their cooperation and integrate both factions into state forces.
Local news channel al-Nabaa showed footage of military vehicles carrying Misrata signs opening fire on Sunday.
Heavy smoke could be seen above the airport, the main gateway into the north African oil-producing nation.
"All domestic and international flights have been halted," an airport official said.
Nabaa footage showed a Libyan Airlines plane and a transport aircraft engulfed in smoke while vehicles fired anti-aircraft volleys.
The news station said that a previously unknown militia called Stability and Security Force had entered the airport area.
Social media websites said that several rockets hit the airport perimeter and pictures posted on Facebook showed thick smoke at what was said to be the parking area in front of the main terminal.
(Reporting by Feras Bosalum and Ulf Laessing; Editing by David Goodman)