A suicide bomber killed eight people during religious celebrations in northern Afghanistan Sunday.

The attack in Baghlan province, which came on the first day of the three-day Eid al-Adha, or Feast of Sacrifice, was condemned by Afghan officials as un-Islamic.

Two days earlier, the Taliban movement's supreme leader, Mullah Mohammed Omar, had issued an Eid message in which he called on his fighters to make a concerted effort to avoid causing civilian casualties. His statement Friday called for the Taliban to investigate attacks that kill civilians and to punish their own fighters who carry them out.

“If it is irrefutably proven that the blood of innocent Muslims is spilled by the negligence of mujahedeen then a penalty should be implemented in accordance with Shariah,” he said, referring to the religious law. “The mujahedeen have to take every step to protect the lives and wealth of ordinary people in accordance with their religious responsibility,” said his statement, which was issued in five languages.

The victims in Sunday's attack included three commanders of the militias known as Arbakai who appear to have been the targets, according to the provincial governor, Munshi Abdul Majid. The other people who were killed, as well as the 18 people wounded, were civilians, he said.

The attack may also indicate weakening control by Mullah Omar and other traditional Taliban leaders.