"The criticism is a distortion and trivialization of a major threat to international peace," he wrote in The Washington Post.

Ekeus, who led United Nations inspectors from 1991 to 1997, said no weapons have yet been found because after the first Gulf War, Iraq had shifted its focus from producing warfare agents to designing and engineering them.

Iraq goal was to allow "production and shipping of of warfare agents and munitions directly to the battlefield in the event of war," he said.

"Many hundreds of chemical engineers and production and process engineers worked to develop nerve agents, especially VX, with the primary task being to stabilize the warfare agents in order to optimize a lasting lethal property," he said.

"The real chemical warfare threat from Iraq has had two components. One has been the capability to bring potent chemical agents to the battlefield to be used against a poorly equipped and poorly trained enemy.

"The other is the chance that Iraqi chemical weapons specialists would sign up with terrorist networks such as al-Qaeda -- with which they are likely to have far more affinity than do the unemployed Russian scientists the United States worries about," he wrote.

The fall of Saddam Hussein opened the door for diplomatic initiatives to rid the Middle East of weapons of mass destruction and to bring stability to the region, especially with the possibility of peace between Israelis and Palestinians, he said.

"This is enough to justify the international military intervention undertaken by the United States and Britain," he said.

President George W. Bush based his justification for the US-led war on his contention that Iraq possessed biological, chemical or nuclear weapons and so threatened US security.

The failure of US forces to discover such weapons has become a political issue in Washington, especially as the United States continues to suffer casualties in Iraq.

WAR.WIRE