Four foreigners and an Afghan interpreter were killed when a Taliban suicide bomber detonated his vehicle near Kabul International Airport on July 22.
Deputy Interior Minister General Mohammad Ayoub Salangi said the attacker drove a motorbike filled with explosives to the entrance of a complex housing foreign advisers to the Afghan government.
But Najib Danish, a spokesman for the Afghan Interior Ministry, said that the early morning attack targeted a compound called "Camp Gibson," which houses the offices of DynCorp International, a U.S. military contractor that trains Afghanistan's counter narcotics police force.
"According to the reports we have, all those killed were Nepalese citizens who were guarding the compound's main gate," he told Radio Free Afghanistan.
But other reports said that at least one of those killed was a Pilipino or Peruvian.
Taliban spokesman Zabihullah Mujahid claimed responsibility for the attack, which also left several people wounded.
The explosion follows a string of attacks across Afghanistan in an escalation of violence typical of summer months.
On July 21 Afghan officials said at least 60 people were killed in separate attacks across the country.
At least eight policemen and 15 militants were killed in a gun battle that lasted for days in the northern Faryab province. Ahmad Javid Bedar, a provincial government spokesman, said the shoot-out began on July 18 after more than 300 Taliban fighters attacked police checkpoints.
A suicide attack in the southern province of Helmand killed one civilian and one policeman. Defense ministry officials said military operations in Khost, Kandahar, Helmand, and Parwan provinces had killed 31 militants on the same day.
On July 17, four militants were killed by members of the Afghan elite police force after they attacked a building under construction on the perimeter of Kabul's international airport, firing rocket-propelled grenades and automatic weapons.
Militants often fire rockets on the airport, causing little damage, but attacks on the heavily guarded facilities around the airport are rare, as these buildings are well-guarded by police and soldiers.
Scores of civilians were killed after a truck bomb exploded at a market in the remote Orgun district in the southeastern Afghan province of Paktika on July 15.
Reports suggest the escalating violence in Afghanistan is exacerbated by a large influx of Pakistani militants into Afghanistan in the aftermath of an ongoing military offensive in a northwestern Pakistani tribal region.
The Pakistani military claims to have killed hundreds of militants since mid-June in the North Waziristan tribal region that borders Afghanistan.
Based on reporting by Reuters, AP, DPA, Daily Beast, New York Times, Washington Post and AFP