BAGHDAD Ñ A key figure in the Al Qaida-aligned movement in Iraq has been killed in a U.S. air strike.

Islamic sources said the spiritual leader of the Tawhid and Jihad group was killed in a U.S. air strike on Sept. 17. They said Sheik Abu Anas Al Shami, a Palestinian, was the target of a U.S. missile strike as he was being driven from Faluja to Baghdad.

The U.S. strike marked the greatest blow to the Tawhid and Jihad movement, led by Abu Mussib Al Zarqawi, regarded as the most lethal insurgent in Iraq. Tawhid has claimed responsibility for most of the abductions and executions of foreign contractors for the U.S. military as well as car bombings throughout Iraq. The latest execution was that of U.S. contractor Eugene Armstrong on Sept. 20.

"We have had a lot of good effect against the Zarqawi network in the past several weeks," U.S. Central Command chief Gen. John Abizaid said in Washington on Wednesday. "We'll continue to work against them as long as it takes. We will find him, root him out and destroy him and his organization, and we'll do it as quickly as we possibly can."

Al Shami, regarded as the No. 2 figure in Tawhid, was first reported killed in an air strike in Faluja on Sept. 17. But over the last day his death was confirmed by his family in Amman. They said that for more than a year Al Shami had been protected by Sunni tribes that opposed the U.S. presence in Iraq.

The Islamic sources said Tawhid has been struck by a series of attacks that targeted senior insurgents over the last week around Faluja. They said that at least one senior operative has been captured during a joint Iraqi-U.S. military operation.

Al Shami was said to have narrated several Tawhid announcements that were posted on the Internet in 2004. In one tape, Al Shami, also known as Omar Yusef Jumah, threatened to kill Iraqi Prime Minister Iyad Alawi.

Islamic sources said Al Shami joined Tawhid around 2002. They said he left Amman for Baghdad soon after the U.S. military defeat of the Saddam Hussein regime in April 2003.