The Washington Post newspaper says U.S. officials are treating as credible a report that Islamic extremists linked to al-Qaida recently acquired a chemical weapon in Iraq.

The Post says U.S. officials believe the weapon involved was the nerve agent VX and that it was smuggled by a courier overland into Turkey.

The newspaper says U.S. officials describe the source of the information as "sensitive and credible."

If the report proves to be true, it would be the first known acquisition of a chemical weapon other than cyanide by al-Qaida or any of its affiliated terrorist groups. It would also run counter to Iraq's assertion that it has destroyed all of its chemical weapons.

U.S. Defense Secretary Donald Rumsfeld was asked about the al-Qaida-Iraq link by NBC television during his visit to the Persian Gulf state of Qatar:

"There are al-Qaida connected to Iraq who have used that country just as there are al-Qaida in Iran and Pakistan and the United States and other countries and we also know that the al-Qaida and other terrorist networks have actively sought to gain access to chemical and biological and radiation weapons," secretary Rumsfeld said.

The Post report says U.S. officials did not know the intended target of the nerve gas but that they were concerned it might be used somewhere in Europe or in the United States.

A spokesman for U.S. Homeland Security Director Tom Ridge says there is no concrete evidence that al-Qaida has obtained chemical weapons.