The U.S.-led group that scoured Iraq for weapons of mass destruction has found no evidence Iraq hid such weapons in Syria before the U.S. invasion in March 2003, according to a final report on the investigation.

The 1,700-member Iraq Survey Team, responsible for the weapons hunt, also said in a report released late on Monday it found no Iraqi officials with direct knowledge of a transfer of weapons of mass destruction developed by former President Saddam Hussein.

President Bush and other U.S. officials cited a grave threat posed by Iraq’s chemical and biological weapons and Baghdad’s efforts to acquire a nuclear arms capability as a justification for war. No such weapons were found but U.S. officials said it was possible Saddam sent them to Syria for safekeeping.

The report is the final addendum to the investigators’ September report that concluded prewar Iraq had no WMD stockpiles of biological and chemical weapons and that its nuclear program had decayed before the U.S.-led invasion.

The Iraq Survey Group, led by CIA special adviser Charles Duelfer, wrapped up its physical searches for weapons of mass destruction last December.

The new report posted on the CIA Web site said: “Based on evidence available … it is unlikely that an official transfer of WMD material from Iraq to Syria took place. However ISG was unable to rule out unofficial movement of limited WMD-related materials.”

It said investigators “found no senior policy, program or intelligence officials who admitted any direct knowledge of such movement of WMD.”

“Indeed, they uniformly denied any knowledge of residual WMD that have been secreted to Syria,” the report said.

The report said the WMD investigation had gone as far as feasible and there was no reason to continue holding many of the Iraqis who had been detained in the process.

“After more than 18 months, the WMD investigation and debriefing on the WMD-related detainees has been exhausted,” the report said.

It noted there was a risk some Iraqi scientists might share their skills with insurgents or terrorists. The report added the pool of scientists who still possessed potentially dangerous expertise was shrinking.