A coalition bomb killed 12 Afghan police, and militants kidnapped at least 15 medical staff in volatile Afghanistan on Thursday, officials and reports said.

Major Matthew Hackathorn, a spokesman for the US-led coalition forces, told Xinhua a coalition aircraft dropped a bomb in Waza Khwa district of the southeastern Paktika province, destroyed two trucks, and "killed all persons in them."

"An investigation was ongoing," he said.

A roadside bomb killed an Afghan soldier when some Afghan and coalition troops were patrolling in the district, Hackthorn said.

A coalition aircraft rushed to the scene and dropped the bomb as some extremists were found there, he added.

Reports quoted provincial governor Akram Ekhpul Wak as saying 12 border police were killed by the mistaken bomb.

He said the provincial government would launch an investigation into the incident.

However, coalition forces said in a latest statement that they are confident the two trucks destroyed by coalition aircraft were the two same ones carrying the extremists and fleeing the site.

Afghan President Hamid Karzai expressed his shock and anger to this deadly incident.

"I am extremely saddened by this tragic incident and I want an immediate investigation to find out what exactly happened," Karzaisaid in a statement, which said at least 10 policemen were killed in the bombing.

He said he has repeatedly asked coalition forces to take maximum caution while carrying out operations.

Meanwhile, a bus carrying 15 medical staff was kidnapped by unknown militants in the southern Kandahar province on Thursday morning, head of the provincial refugee department told Xinhua.

A medical team of the department traveled by bus to a refugee camp in Jarai district and was stopped by some militants on the way, said Agha Jan Hazari.

However, Abdullah Fahim, the spokesman for Public Health Ministry, said 20 persons were abducted in the incident, according to reports.

Coalition forces said on Thursday that eight extremists were killed in the eastern Kunar province.

Some extremists attacked coalition troops in Asadabad district on Wednesday, and the troops responded with small arms, machine gun fire and grenades, killing eight enemies.

The forces also said a coalition soldier, whose nationality was yet to be announced, was killed on Wednesday by a Soviet-era mine in Bermel district of Paktika province.

On Thursday morning, eight Afghan police were injured as a suicide bomber detonated himself in a police checkpoint in the southern Uruzgan province.

Hours later, a suicide bombing attack injured one NATO soldier in the neighboring Kandahar province, a local Afghan commander Ghulam Sakhi told Xinhua.

The attack occurred some 10 km east of Kandahar city, the provincial capital, when some Afghan and NATO troops were passing by.

The latest attacks and incidents are among a spate of rising violence in Afghanistan, which has thrust it into its worst period of bloodshed after the Taliban regime was toppled in late 2001.

Over 1,800 people, mostly Taliban militants, have been killed this year in this central Asian country.

The number includes more than 80 foreign troops, most of whom are Americans.

(Xinhua News Agency August 18, 2006)