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 (search) 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 (search), 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 (search), 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 and 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 Qaeda holdouts in the south and east of the country are operating. Several dozen U.S. troops are based in neighboring Herat.

Rebels of the former ruling Taliban regime and Al Qaeda, active in the south and east of the country, have targeted aid workers over the past year in an apparent attempt to undermine efforts by the U.S.-backed government to rebuild the country after a quarter century of war.

A remote-control bomb exploded Wednesday in eastern Nangarhar province, injuring two Afghan election workers, said Gen. Mohammed Mustafa, an Afghan border security official.

Three other Afghans in the vehicle escaped unhurt from the blast, in Momand Dara area, about 20 miles east of the provincial capital Jalalabad, Mustafa said.

Security is also poor in areas of the north, because of the continuing influence of rival warlords. Armed robberies are regularly reported in the region. But attacks by suspected Taliban militants are rarely reported in the north.

"It's the first time anything like this has happened here," Badghis Gov. Azizullah Afzali said.

Growing violence in recent months -- including killings of NATO peacekeepers in the capital and attacks on U.S. forces -- has cast a long shadow over plans for general elections in September, seen as key to rehabilitating the war-battered nation.

Last week, a senior European Union official accused troops with the U.S.-led coalition in Afghanistan of endangering humanitarian workers by operating in civilian vehicles and clothes, raising local hostility, and said that 23 aid workers had been killed in Afghanistan since March 2003.

In May, gunmen killed three U.N. election workers, including two British security consultants, in eastern Nuristan province. The Taliban claimed responsibility. Two other foreigners were found bludgeoned to death in Kabul the same month, but the motive for the killings remain unclear.

In November, two gunmen killed Bettina Goislard, a 29-year old worker for the United Nations High Commission for Refugees, in the eastern city of Ghazni, the only foreign U.N. staff member slain since the fall of the Taliban.