Heavily armed Afghan insurgents launched a suicide attack on a NATO airbase inside Kabul's international airport and seized two nearby buildings after dawn on Monday.
Troops of Afghan military rushed to the scene in an attempt to clear off the buildings under construction floor by floor.
Explosions and rounds of fire were exchanged for every two hours since the attack began. The US embassy sounded its "duck and cover" alarm and made an announcement on the loudspeakers that the alarm was not a drill. Helicopters were seen hovering over the area, with gun shots and explosions being heard irregularly.
"An explosion... occurred after which a group of suicide attackers entered a building (near) Kabul airport, and started sporadic shooting," Hashmat Stanikzai, Kabul's police chief, said in a statement.
"Now the area is sealed off and a stand-off between security forces and the attackers is ongoing."
Emyatullah, a resident living close to the airport told Guardian, "It started just after dawn prayers and I counted about a dozen explosions, mostly RPG fire, coming from the airport."
Afghan troops handled the suicide attack sans the aide of international forces, reported BBC.
However, AFP quoted a NATO-led coalition spokesperson as saying, "There were personnel from the International Security Assistance Force (ISAF) with Afghan forces but Afghan forces led the operation."
The attack began at 4:30 am just hours after Afghan president Hamid Karzai took off from the airport to Qatar. A Taliban spokesman has claimed responsibility for the attack.
The last major attack on Kabul was on 24 May when the insurgents launched a suicide attack on a compound of the International Organization for Migration (IOM).
Afghanistan has been ravaged by war since civil war broke out in 1992. Afghan forces will be taking over from the US-led coalition forces, which are slated to leave the country by the end of 2014.