A police officer at the scene, Jan Agha, said the attackers have not entered the International Election Commission's compound, which is heavily secured.
He was quoted by AP as saying that the attackers are about 500 meters from the compound in a three-story house. He said there's no immediate information about casualties.
It's the latest in a series of high-profile attacks that come as the Taliban have stepped up a campaign of violence to disrupt presidential elections, which are due to be held in a week.