Baghdad, Iraq ? The United States is inviting a group of international experts to inspect two mobile labs suspected of being used by Iraq as biological weapons facilities, a senior military commander involved in the weapons hunt told The Associated Press on Tuesday.

Although the laboratories do not represent proof that Iraq had biological weapons, American officials believe their only purpose was for making such weapons. Outside confirmation could help legitimize one of the Bush administration’s main reasons for going to war.

“We’re going to invite a special team, an international team of experts to take a look at the labs,” said Col. Tim Madere, the chemical weapons specialist for the U.S. Army’s V Corps, one of the main units occupying Baghdad.

Madere said the Pentagon would provide further details about the international team in coming days. The two labs already have been inspected by U.S. and British technical experts and a group of scientists from coalition countries, Madere said in an interview.

Earlier this month, Pentagon officials said the discovery of the first trailer — seized at a checkpoint near the northern Iraqi city of Mosul on April 19 — could prove Iraq had active programs to produce weapons of mass destruction.

Troops from the Army’s 101st Airborne Division found the second trailer May 9 at al-Kindi, a former missile research facility in Iraq. The trailer is similar to another found last month in the same area that U.S. officials believe was a mobile germ-weapons workshop.

Some equipment from the latest trailer had been looted, and there were indications such as unfinished welding that the apparatus was incomplete.

Stephen Cambone, the undersecretary of defense for intelligence, said in Washington earlier this month that he didn’t know whether the discovery of the first lab represented a “smoking gun.” But he said British and American technical experts had “concluded that the unit does not appear to perform any function beyond … the production of biological agents.”

Saddam Hussein’s regime had insisted that Iraq had destroyed all its chemical and biological weapons in the early 1990s as required by U.N. resolutions imposing sanctions after Iraq’s invasion of Kuwait. U.N. weapons inspectors, who spent 3 1/2 months in Iraq just prior to the war, found no evidence to refute the Iraqi claims.

President Bush cited Saddam’s failure to eliminate Iraq’s biological and chemical weapons programs as one of his main reasons for launching the war, which ousted Saddam last month.