An attacker driving an ambulance packed with explosives detonated them Saturday in Kabul, leaving 40 people dead and 140 others injured, Afghan officials said.
Taliban spokesman Zabiullah Mojahid claimed responsibility for the attack.
The blast occurred around 12:45 p.m. local time after the vehicle passed through a security checkpoint, Interior Ministry spokesman Nasrat Rahimi told CNN.
Police identified the attacker at a second checkpoint but couldn't stop him before he detonated the explosives near the old Ministry of the Interior building, Rahimi said.
The injured have been taken to hospitals across the Afghan capital, said spokesman Wahid Majrooh of the Ministry of Public Health, who confirmed the casualties.
Afghanistan's Chief Executive, Abdullah Abdullah, condemned the attack, describing it as "insane, inhuman, heinous and a warcrime," via his official Twitter account.
He also called on the international community to "take further action" against "state sponsored terrorism."
"Our priority and focus right now is to help those in need and provide the best treatment for those wounded," he wrote. "This is the moment when we all need to stand together and punch our enemy hard. This is enough!"
The blast comes a week after gunmen attacked the Intercontinental Hotel in Kabul, killing at least 22 people during a 12-hour standoff with security forces.
Of those killed, 14 were foreign nationals -- including four Americans -- and eight were Afghans, according to the Ministry of Interior. Six gunmen were killed by Afghan security forces. The Taliban claimed responsibility for the assault.
ISIS militants on Wednesday attacked the offices of British aid agency Save the Children in the eastern Afghan city of Jalalabad, killing at least four people and injuring dozens.