(CBS) A senior Iraqi general Thursday dismissed as "ridiculous" a published report that Iraq may have provided nerve gas to Islamic extremists affiliated with al Qaeda.

"This is really a ridiculous assumption from the American administration," Lt. Gen. Hossam Mohammed Amin told a press conference. "They know very well we have no prohibited substances."

Administration officials also tried to play down the report in The Washington Post that U.S. intelligence had received credible reports of a transfer of chemical weapons — possibly VX nerve gas — to an extremist group in the past month.

A senior administration official, commenting on the Post report, told The Associated Press that U.S. intelligence had uncorroborated information that Islamic extremists with ties to al Qaeda may have received a poisonous substance. The official, speaking on condition of anonymity, said the U.S. does not know whether the material was nerve gas nor whether the extremists are linked to Saddam's government.

But Defense Secretary Donald Rumsfeld said the possibility of such a sale "should come as no surprise to anybody."

Rumsfeld told ABC's Good Morning America he had not seen the article, but "I have seen other information over a period of time that suggests that could be happening." He said it has been know for many months, "probably years that the terrorist states have chemical weapons and have relationships with al Qaeda and that al Qaeda is trying to get such weapons."

The suspected deal would mark the first time an al Qaeda linked group was known to have obtained a chemical weapon other than cyanide. It would also be the first direct evidence of a link between Iraq and terrorism, which the Bush administration has long said existed.

Administration officials told The Post the source of the material was still unknown, and that it was uncertain the deal involved nerve gas. One official told the newspaper the report could be a mere hypothesis.

Even if the sale did occur, it's not certain that the Islamic group was buying the weapons for Al Qaeda. Nor is it clear that the chemical agent was in weaponized form.

On the question of whether Iraqi President Saddam Hussein knew of the sale, there is no solid evidence, although sources consider it unlikely that such a deal could transpire without Saddam's knowledge, the paper said.

But one official told The Post the report of the weapons sale stood out from the hundreds of leads screened by U.S. intelligence every day.

"The way we gleaned the information makes us feel confident it is accurate," said the official. "I throw about 99 percent of the spot reports away when I look at them. I didn't throw this one away."

The suspected weapons sale could be linked to two threat warnings in the past week. One, called a Turkey Defense Terrorism Threat Awareness Message, warned U.S. troops of a possible chemical attack on the air base at Incirlik, Turkey, which is a major hub for American military operations in the region. Another alert came from European governments warning, the event of war, of a possible gas attack on the mass transit system of a major U.S. city.

VX nerve gas is among the deadliest chemical agents. It is more dangerous than Sarin gas, the agent used in the deadly 1995 Tokyo subway attacks. British scientists developed it in 1952 and apparently traded it to the United States for information on nuclear weapons.

According to government health information, VX gas usually kills within fifteen minutes. The only antidotes are the extremely strong drugs atropine, pralidoxime chlorida and diazepam.

Iraq has admitted to stockpiling VX. It would be difficult for an terrorist group to develop the gas on its own because of the "difficulty of manufacture and control of precursor chemical," according to a 2001 General Accounting Office report.