Hundreds of protesters, angered by an overnight NATO raid that they believed had killed four civilians, clashed on Wednesday with security forces on the streets of a northern Afghan city.

At least 11 people were killed as the protesters fought with police and tried to assault a NATO outpost in the city of Taloqan, the capital of Takhar province, government officials said. Some 50 were injured, including some police officers.

The NATO raid they were protesting took place hours before on the outskirts of the city. The coalition said four insurgents died in the operation and that two others were detained.

Controversial night raids

Night raids targeting insurgents regularly stir up controversy in Afghanistan, where angry residents often charge the next day that international forces go after the wrong people or mistreat civilians as they search compounds. Success by NATO in reducing civilian casualties and agreements to conduct night raids alongside Afghan forces have not managed to stem the tide of accusations.

Provincial Gov. Abdul Jabar Taqwa said the four casualties from the raid were two women and two men who were killed when troops burst into a home in an area known as Gawmal late Tuesday night. He said that no one in his government was informed about the raid and that NATO acted unilaterally.

NATO confirmed it killed four people, two of them women, but said all were armed and tried to fire on its troops. NATO said the raid was conducted by a "combined Afghan and coalition security force," according to coalition policy.

A spokesman for NATO forces said that the governor was contacted ahead of the raid.

"It is standard practice in Takhar province to contact the Afghan provincial leadership prior to an operation. In this case, calls were placed to the provincial governor six times prior to the operation," Maj. Michael Johnson said. He also reiterated that Afghan forces took part in the operation.

"We are aware of the claims of civilian casualties, and are looking into them," Johnson added.

Provincial police chief Gen. Shah Jahan Noori said he had not been informed of the operation and said none of his officers were involved. Army officials could not be reached immediately for comment.

Insurgents targeted

NATO said that the raid targeted a man working with the Islamic Movement of Uzbekistan — an insurgent group that is powerful in the north. The man was involved in arms trafficking and building explosives, NATO said. The alliance did not say if he was killed or captured.

It is rare for women to be part of an insurgent fighting force in Afghanistan, but not unheard of. There have been cases in the past of women fighting with the insurgency, including as suicide bombers.

NATO said in its statement that one of the women was armed with an assault rifle and tried to fire on the troops. The other woman was armed with a pistol and pointed her gun at the security force as she was trying to escape the compound.

On Wednesday, hundreds of people gathered on the road from Gawmal to Taloqan and carried the four bodies on platforms as they marched into the city, according to an Associated Press Television News cameraman at the scene. They shouted insults at Afghan President Hamid Karzai and the United States as they pumped their fists in the air.

"Death to Karzai! Death to America!" they yelled.

The governor, Taqwa, estimated that there were about 1,500 demonstrators.

The protest turned violent as some in the crowd started looting shops and throwing stones at a small German base in the city. Police were out throughout the city trying to calm the crowd, Taqwa said. Gunfire could be heard in a number of neighbourhoods and troops at the German outpost shot off rounds in an attempt to disperse the crowd outside their walls.

The German military said in a statement that the demonstrators threw hand grenades and Molotov cocktails into the base, injuring two German soldiers and four Afghan guards. The German soldiers, one of whom was slightly injured and one somewhat more seriously, were both in stable condition, the military said.

Meanwhile, Afghan officials say at least 10 people have been killed in a bomb attack on a police bus that was carrying people to a police academy in eastern Afghanistan.

Nangarhar province government spokesman Ahmad Zia Abdulzai said the blast occurred Wednesday afternoon on a road running through Jalalabad, the major city in the east. He said it was not yet clear if the bus was attacked by a suicide bomber or if it hit a roadside bomb.

A doctor at the main hospital in the city said at least 10 people had been killed and 20 wounded. Dr. Saif Ul-Rahman said it was not known how many of the dead were police officers and how many were civilians.