Gen. David Petraeus laid further blame on Iran for violence in Iraq on Sunday, charging that Tehran's ambassador to Baghdad was once a member of Iran’s elite Revolutionary Guards force.

Petraeus added that Iran has been aiding Iraqi rebels with training and gifts of high-powered weaponry.

"They are responsible for providing the weapons, the training, the funding and in some cases the direction for operations that have indeed killed U.S. soldiers," Petraeus told reporters in Diyala Province.

Without citing any specific intelligence, Petraeus labeled Hassan Kazemi-Qomi, Iran's envoy to Baghdad, as a former member of the Revolutionary Guards Quds force. But he did not suggest that action would be taken against the ambassador.

"Now he has diplomatic immunity and therefore he is obviously not subject [to scrutiny]. He is acting as a diplomat," he said.

The Iranian Foreign Ministry dismissed the charges agaisnt Kazemi-Qomi “baseless” accusations, according to the Islamic Republic News Agency.

"They repeatedly link those arrested or killed in the bombardments with the Quds force. If they can, they announce names of those people or hand over the names to the Islamic Republic of Iran," Mohammad-Ali Hosseini told IRNA.

The Iranian Revolutionary Guards Corps has been under intense scrutiny by U.S. officials. In August, President Bush signed an executive order branding them as a “specially designated global terrorist.”

Iran returned the “favor” last week with a parliamentary order that gave the U.S. Army and the CIA the same distinction.

Separately on Sunday, Iranian President Mahmoud Ahmadinejad said Tehran will not hold talks with Washington until the U.S. changes its attitude.

"We firstly say that we never asked for negotiations with the United States. Negotiations with the U.S. will happen when the U.S. government applies basic changes in its behavior and attitude," Ahmadinejad was quoted as saying.

Last week, Bush told a group of businessmen in Pennsylvania that he would negotiate with Iran if it suspended its nuclear program. He made similar comments in an interview aired Friday on Al-Arabiya TV.

FOX News' David MacDougall and The Associated Press contributed to this report.