Jamie Graybeal, a spokesman for the U.S.-led international military alliance, said all coalition compounds in Kabul were currently secure.
He said he was not aware of any casualties among members of the coalition.
The U.S. and Italian embassies as well as the Afghan presidential palace are also located near the site of the blast.
The Afghan Interior Ministry said six people, all civilians, were killed and five others were wounded.
The bombing was carried out by a 28-year-old militant from Logar province, south of Kabul, a Taliban spokesman said.
However Kabul deputy police chief Daud Amin said eyewitnesses reported seeing a teenage boy, who was about 13 or 14 years old, walking in the area carrying a bag.