Taliban leader Mullah Omar is urging his followers to avoid killing Afghan civilians.

Omar said militants should not harm civilians in order to maintain good relations with the general population.

His remarks were posted on the Taliban's website ahead of the Muslim holiday Eid al-Adha or the “Feast of Sacrifice.”

In his statement, Omar says Afghan civilians should take precautionary measures to keep themselves safe from attacks, including staying away from U.S. troops on patrol.

Civilian deaths have increased as the war in Afghanistan enters its 11th year. The United Nations says the number of civilians killed went up by 15 percent in the first half of 2011, with nearly 1,500 deaths due mostly to insurgent attacks.

The British Defense Ministry said Friday an insurgent attack killed a British soldier the day before, while he was on patrol in the Nahr-e Saraj district of southern Helmand province.