International troops and Afghan security forces arrested the police commander in Mahmud Raqi, a district of mainly French-patrolled Kapisa province north of Kabul, the NATO-led International Security Assistance Force (ISAF) said.

"A known IED facilitator, he has been involved in the storage, distribution and installation of IEDs on the roads surrounding Mahmud Raqi," ISAF said in a statement. IEDs, or improvised explosive devices, are the military term for homemade bombs, by far the most lethal weapon used by insurgents.

"He is also involved in bribery and corruption related to road refurbishment. He has been clearly linked to criminal activities including a murder during the summer of 2009," the statement said. It did not name the commander.

Western troops are struggling to train an Afghan police force to eventually take over security in the country so they can withdraw, but acknowledge that the force is plagued by corruption, incompetence and infiltration by insurgents.

Last November, an Afghan policeman shot dead five British soldiers in southern Helmand province. The Taliban said he was one of their fighters who had infiltrated the force.

Many Afghans also complain about police corruption, one of the reasons that some have turned to the Taliban to provide law and order.

President Hamid Karzai has promised to root out corruption, but prosecutions are extremely rare.