Gunmen entered a Kabul government compound in Afghanistan after detonating a car bomb, officials said.
The attack occurred outside Afghanistan's ministry of public works.
Afghan security forces have killed two of the attackers and freed 200 employees trapped inside one of the buildings occupied by the gunmen, the government said.
Afghanistan's ministry of labour said a number of gunmen had entered the compound.
"There are still some hostages with the enemy and a clearance operation is ongoing," Interior ministry deputy spokesman Nasrat Rahimi said.
It is still not known who is responsible for the latest attack.
At least four people have been wounded, health ministry spokesman Wahid Majroh said.
Today's attack was the biggest in Kabul since November 28 when the Taliban detonated a car bomb outside the compound of British security firm G4S, killing at least 10 people