Interior ministry spokesman Nasrat Rahimi said the death toll had risen to nine, including five members of the Afghan security forces, a guard at Counterpoint and three civilians.
Nusrat Rahimi, spokesperson for the Ministry of Interior Affairs, said the target of the attack was Counterpart International, an NGO headquartered in the United States that has been operating in Afghanistan since 2005.
The NGO’s office is located near the attorney general’s office in the Shahr-e-Naw area in Kabul.
Intermittent gunshots and explosions were heard as special forces, backed by advisers from foreign forces, surrounded the site and engaged the attackers in a standoff. Authorities cordoned off the area as they sent in ambulances and police trucks.
Rahimi said at least 80 employees of the NGO were rescued and security forces were clearing other buildings in the area.
“Two floors of the building have been cleared and, to avoid civilian casualties, the operation is being undertaken with caution,” Rahimi said.
Taliban spokesman Zabiullah Mujahid said the group attacked the NGO because it was involved in “harmful Western activities” in Afghanistan. He did not elaborate on what those activities were.
The blast came only two weeks after armed men targeted the communications ministry in central Kabul, killing at least seven people. That attack was claimed by the Islamic State of Iraq and the Levant (ISIL or ISIS).
Meanwhile, representatives of the US and Taliban continue their negotiations in Qatar aimed at bringing an end to the nearly 18-year-long conflict.
The talks follow a peace summit in Kabul last week where President Ashraf Ghani offered a ceasefire from the first day of Ramadan, which was refused by the Taliban.
Last year, the Taliban announced a three-day ceasefire at the end of Ramadan after Ghani declared a unilateral truce for eight days earlier in the month.
It was first formal nationwide ceasefire since the US-led invasion of 2001 and saw unprecedented scenes of reconciliation and jubilation across the country.