Libya: Tripoli International Airport
A general view of the entrance to the airport in TripoliReuters

Heavy gunfire is being reported in Libya's Tripoli International Airport as rival Islamist groups are involved in fierce clashes.

The Islamist militias staged an attack on the Zintan outfit, the armed group which controls the capital's airport, in a bid to seize the facility.

"Clashes followed between the Zintan militia who control the airport and rivals who want to drive them out," a Libyan official told the AFP and added that "rockets struck inside the airport perimeter".

A British Airways flight to London and another Turkish Airlines plane have been suspended following the attack.

The Operations Cell of Libyan Revolutionaries, a bloc of Islamist extremists, has claimed the attack.

"The revolutionary forces arrive within the perimeter of Tripoli airport and clash with armed groups inside," the coalition said on its Facebook page.

As the restive country awaits controversial election results, the country's second city Benghazi has also witnessed violence.

"The United States is deeply concerned by the ongoing violence in Libya and dangerous posturing that could lead to widespread conflict there. We stress the vital role Libya's Constitution Drafting Assembly plays in building the new country for which Libyans sacrificed so much during the revolution" said US State Department spokesperson Jen Psaki on the eve of the airport attack.

The country has been embroiled in a bloody violence since dictator Muammar Gaddafi was expelled three years ago.

The Zintan group, former rebel militia, has been a faction that is supporting the liberals in the Libyan government following the absence of a powerful administration.