(London) -- An Afghan policeman gunned down five British soldiers at a checkpoint in Afghanistan's volatile Helmand province.

The Taliban say the shooter was one of their fighters who had infiltrated the police force, adding similar attacks will be carried out.

An Afghan defense official said the policeman is still at large, but a Taliban spokesman said it's not known whether he is still alive or dead.

The British soldiers were killed while training Afghan forces.

The fatal shooting occurred the day after Afghan election officials cancelled a run-off election to give President Hamid Karzai a second term in office when his challenger dropped out.

The U.S. and Britain are concerned about corruption in Karzai's government and mounting troop deaths.

General Stanley McChrystal, the top U.S. and NATO commander in Afghanistan, says the shooting incident will not prompt a change in the training of Afghan security forces.

Meanwhile, a former British foreign ministry official says Britain should withdraw most of its troops from Afghanistan to focus on securing its own borders against terrorists.

　

(Copyright 2009 by VERTEXNews/Newsroom Solutions)