KABUL, December 17 (RIA Novosti) - Afghan National Army and NATO-led units have killed about 50 Taliban militants in a special operation that started on Friday in the southern Helmand province, a Defense Ministry source said on Wednesday.

A Taliban spokesman denied the losses, and said 11 Afghan servicemen had been killed.

In the same province, a British soldier was killed in a Taliban attack on Monday. Taliban gunmen also killed two policemen and wounded three others in a sneak-raid on a police checkpoint in Helmand on Tuesday morning.

This year has seen the worst violence in Afghanistan since the overthrow of the Islamic Taliban movement in 2001, with the south of the country the worst affected.

A report this month by the International Council on Security and Development think tank said the Taliban had a permanent presence in 72 percent of Afghanistan and were 'closing a noose' around the capital, Kabul.