KABUL: Explosions and gunfire rang out after the Taliban Thursday attacked Kabul airport in the militants' latest brazen attempt to steal the initiative with the country in the grip of a presidential power struggle.

The overnight attack on an airport outbuilding came ahead of an unprecedented audit of ballot papers from last month's presidential run-off election, designed to resolve the political crisis that threatens to renew Afghanistan's dangerous ethnic fissures.

Some 23,000 ballot boxes are being transported by the Afghan army and Nato forces to the capital, where they will be examined at 100 verification stations in a process starting Thursday.

Nato's International Security Assistance Force (ISAF) — whose main Kabul compound lies next to the civilian airport — is providing air transport for some 40 percent of the votes as it winds down its deployment after more than a decade of war.

The interior ministry said a group of insurgents had opened fire with automatic weapons and rocket-propelled grenades after seizing a building under construction at the airport.

The attack began around 4:30 am and was still underway, but no casualties have been reported so far, the ministry said.

“The situation will be brought under control before long,” General Ayub Salangi, the deputy interior minister, told AFP as security forces armed with automatic rifles took up position.

Civilian flights from the airport north of Kabul have been suspended, another Afghan official said.

ISAF and Afghan military helicopters were seen hovering over the area during the attack, which came after a devastating suicide bombing at a busy market in southeastern Paktika province on Tuesday killed at least 42 people.

Taliban militants claimed responsibility for the attack. “A number of our mujahedeen armed with heavy and light weapons have launched an attack on Kabul International Airport,” the insurgents' spokesman Zabiuhallah Mujahid said in a statement.

The attack came as Afghanistan geared up for the massive poll audit agreed by the two rival presidential contenders, Abdullah Abdullah and Ashraf Ghani, following a deal brokered by US Secretary of State John Kerry.

Election officials expect that the results of the audit, which will take at least three weeks, would be accepted by both candidates after weeks of bitter dispute over fraud claims.

The impasse over the vote to succeed President Hamid Karzai has raised fears of a return to the ethnic violence of the 1990s.

Everyone of the 8.1 million votes cast in the run-off election will be checked for signs of fraud in a painstaking process in Kabul.

The Kabul airport is a prime target for the insurgents. Militants destroyed Karzai's parked helicopter and damaged three other choppers after firing rockets into the airport on July 3.