Kabul, Afghanistan ? Three foreign medical workers and two Afghans were killed Wednesday when their car was ambushed in northwestern Afghanistan, police and the aid agency said. Resurgent Taliban militants claimed responsibility.

The assault was the deadliest on foreign aid workers since the U.S.-led ouster of the Taliban regime in late 2001, and was bound to raise new security fears that already prevent agencies from operating in much of the insurgency-hit south and east.

The group was ambushed in Khair Khana, a village in Badghis province 340 miles west of Kabul, provincial police chief Amir Shah Naibzada told The Associated Press.

An official at aid group Medecins Sans Frontieres, which runs several clinics in the province, said three of its foreign staff and two Afghans died in what “seemed to be a terrorist-type attack,” but added that details were still murky.

An MSF news release later said the foreign victims were a Belgian woman, a Dutch man and a Norwegian man. The MSF said they were members of a medical team, but it did not give their specific jobs.

Naibzada said it was unclear if they were the victims of anti-government militants or robbers. “It’s too early to say who’s behind this,” he said by telephone from a car rushing him to the scene.

But Mullah Abdul Hakim Latifi, a purported spokesman for the Taliban, called AP and said it carried out the attack at 4 p.m. and gave the location where it took place. He threatened more attacks would follow.

“The Taliban was responsible for this attack,” Latifi said. “Those international aid workers were working for the policy of America. There will be more of these attacks in the future.”

Badghis province is far from where most of the 20,000 U.S. troops deployed in the hunt for Taliban and al-Qaida holdouts in the south and east of the country are operating.

Rebels of the former ruling Taliban regime and al-Qaida, active in the south and east of the country, have targeted aid workers over the past year.