Administration officials say their approach was carefully calibrated to focus on concerns that Iran is providing potent weapons used against American troops in Iraq, not to ignite a wider war. “We’re trying to strike the right tone here,” a senior administration official said Monday. “It would have raised the rhetoric to major decibel levels if we had had a briefing in Washington.”

At the State Department, the Pentagon and the Office of the Director of National Intelligence, officials had anticipated resistance to their claims. They settled on an approach that sidelined senior officials including Zalmay Khalilzad, the American ambassador to Iraq, and John D. Negroponte, who until last week was the director of national intelligence. By doing so, they avoided the inevitable comparisons to the since-discredited presentation that Secretary of State Colin L. Powell made to the United Nations Security Council in 2003 asserting that Iraq had illicit weapons.

The White House and the State Department both made clear on Monday that they endorsed the findings presented in Baghdad. Asked for direct evidence linking Iran’s leadership to the weapons, Tony Snow, the White House spokesman, said: “Let me put it this way. There’s not a whole lot of freelancing in the Iranian government, especially when its comes to something like that.”

Sean McCormack, the State Department spokesman, said: “While they presented a circumstantial case, I would put to you that it was a very strong circumstantial case. The Iranians are up to their eyeballs in this activity, I think, very clearly based on the information that was provided over the weekend in Baghdad.”

In Australia, however, Gen. Peter Pace, the chairman of the Joint Chiefs of Staff, told reporters that he “would not say” that Iran’s leadership was aware of or condoned the attacks. “It is clear that Iranians are involved, and it’s clear that materials from Iran are involved, but I would not say by what I know that the Iranian government clearly knows or is complicit,” according to an account posted on the Voice of America Web site.