KANDAHAR, Afghanistan - Afghanistan's interior minister called Tuesday for the disbanding of private security forces after a group of guards that has worked for the U.S. military was involved in the killing of a provincial police chief in the country's south.

In eastern Afghanistan, meanwhile, a suicide bomber wearing a burqa killed a police officer and a girl in an attack on a key Afghan-Pakistan border crossing, officials said.

The killing of Kandahar's top police officer spotlighted the role of shadowy armed groups that frequently operate alongside international military and security forces -- but are not part of known Afghan government security structures.

The shooting Monday also dealt a blow to security efforts in a province from which Taliban leader Mullah Omar once ruled the country.

Interior Minister Mohammad Hanif Atmar said that the 41 Afghan gunmen involved in the killing of Kandahar's provincial police chief had been brought Tuesday to Kabul, the capital, where they will be put on trial.

Atmar said that the various private security forces, which he called "militias," should be disbanded and folded into the legitimate Afghan security structures.

It is unclear how many private militias operate in Afghanistan -- or who, exactly, runs them. However, with violence spiraling in much of the country, foreigners and Afghans alike have increasingly turned to such groups for security.

Little is known about the group involved in the Monday gunbattle, in which Kandahar's provincial police chief Matiullah Qati and five other officers were killed. Afghan officials would not comment on who they are.

U.S. military spokesman, Navy Chief Petty Officer Brian Naranjo, said those involved in the incident "frequently worked with the U.S. military operations," but during the Monday shooting were not acting "in any way, shape or form with the knowledge or support of U.S. forces."

"Their actions yesterday are inexcusable, and they did that on their own," Naranjo said.

Naranjo would not give any specifics about the nature of the operations that these forces were involved in, or their legal status.

The armed group had attempted to free a prisoner held by Afghan authorities inside a government complex in Kandahar shortly before the incident Monday.

U.S. soldiers are deploying to Kandahar later this summer, part of a surge that will see the total number of American forces in the country brought to 68,000, more than double the 32,000 troops here last year.

The Taliban ruled Afghanistan between 1996 and 2001 and were ousted from power following a U.S.-led invasion.

In recent years, the group has made a violent comeback, wreaking havoc in much of the country's south and east forcing the United States to pour in thousands more troops.

In eastern Afghanistan on Tuesday, a suicide bomber who had crossed from Pakistan detonated a blast at the busy Torkham crossing in Afghanistan's eastern Nangarhar province, said Abdul Hadi, a border police officer. Ten other people were wounded.

Torkham is one of the main international border crossings between Pakistan and Afghanistan, leading east into Pakistan's famed Khyber Pass and west toward the Afghan capital, Kabul.

Hadi said the bomber was dressed in an all-covering burqa commonly worn by women in the region and set the blast off in a room, about metres inside Afghanistan, where women are searched before they are allowed to pass the border control.

A police officer and a 12-year-old girl were killed, he said. The wounded included seven civilians and three police officers.

The Taliban militants regularly launch suicide bombings targeting Afghan and foreign security forces, but civilians are often among the victims.

Separately, the U.S.-led coalition launched airstrikes Monday that killed more than a dozen insurgents and destroyed two militant command bunkers in eastern Khost province, the coalition said in a statement.

It is impossible to confirm the casualty numbers because access to the remote, dangerous area is restricted.

The strikes targeted insurgents linked to militant leader Siraj Haqqani, whose network is the most powerful in eastern Afghanistan, the Tuesday statement said. U.S. and Afghan officials believe Siraj commands his operations from Pakistan's tribal areas.

Those targeted were involved in the movement of foreign fighters in Afghanistan, it said. The porous border with Pakistan is their a major transit route into the country.

The Obama administration has declared eliminating militant havens in Pakistan vital to its goals of defeating al Qaeda and winning the war in Afghanistan.