Suspected Taliban (search) militants ambushed a convoy of government census workers in southwestern Afghanistan on Thursday, killing one and wounding 11, officials said.

The 60 workers were traveling in a convoy through Farah province doing preliminary work for the country's first national census since 1979, Gov. Abdul Karim Baravi (search) said.

The attackers were waiting along the road in two cars and escaped after the assault. Five of the census workers were in serious condition, Baravi and U.N. security official Shafiq Khan said.

"Taliban carried out this attack. The attackers were not thieves. They didn't steal anything," Baravi told The Associated Press. The assault occurred about 110 miles west of Kandahar, the capital of neighboring Kandahar province.

Attacks by pro-Taliban and pro-Al Qaeda (search) militants have increased in southern and eastern Afghanistan, forcing U.N. and relief agencies to cut back their work there.

Violence was also reported elsewhere in the southern Afghanistan.

Coalition forces skirmished with suspected Taliban militants on Wednesday, but no American casualties were reported, a U.S. military spokesman said Thursday. The fight occurred near a U.S. base in Khost, not far from the Pakistan border, and involved special American forces, spokesman Maj. Richard Sater said at Bagram Air Base north of Kabul, the Afghan capital.

"An undetermined size of anti-coalition elements directed small arms fire at the location. When coalition soldiers returned fire, the enemy group attacked and retreated toward the Pakistan border. I'm not sure if any of the enemy were killed or wounded," he said.

Sater also said that two American soldiers wounded by a hand grenade in Kandahar on Wednesday were evacuated to Germany for medical treatment.

Kandahar police have said Afghan security forces chased the suspect and arrested him, but only after he threw another grenade, slightly injuring an Afghan police officer.

More than 11,500 U.S.-led coalition forces are hunting down followers of the Taliban and its allies, who in recent months have stepped up attacks in the country's south and east.

Some 35 Americans have died from hostile fire since the October 2001 start of the Afghan war, according to the U.S. military.