The attack destroyed the entrance to a NATO supply company's compound on Monday.

A plume of smoke rose above the scene in the city, where the Taliban have recently staged a series of bombings that have targeted the Supreme Court, the airport, the presidency and a CIA office.

This comes as the US has been pushing for talks with the militant group.

"Four Nepalese guards, one Afghan guard and two Afghan civilians have been killed," Kabul police chief Mohammad Ayoub Salangi told AFP.

The bomb attack left a large crater in the ground, and reduced walls and a guard post to a pile of rubble and twisted steel. Police said some explosive vests were later detonated by security forces.

The Taliban claimed the latest attack, as pressure grows on the Afghan government to secure a peace deal with the militants before international troops pull out.

A Taliban office that opened in the Persian Gulf state of Qatar on June 18 to open talks enraged President Hamid Karzai by styling itself as an unofficial embassy for a government-in-exile.

Karzai broke off bilateral security talks with the Americans and threatened to boycott any peace process altogether.

The Taliban, who have been fighting US-led forces for 12 years, have consistently refused to hold any peace talks with the Afghan government, with militants labeling Karzai as a US agent.

But the Pentagon on Monday expressed optimism over negotiations for a security deal which would allow a "residual" US force to stay in the country with legal immunity.

More than 3,300 US-led forces have been killed in the country since 2001, peaking at 711 deaths in 2010, according to the independent icasualties.org website.

Half of the 68,000 US troops in Afghanistan will reportedly exit by February, and the newly-trained Afghan army and police are increasingly taking the lead in the battle to suppress the Taliban.

The Taliban were deposed in a 2001 US-led invasion for sheltering Osama bin Laden and other al-Qaeda leaders after the 9/11 incidents in New York and Washington.