"I wouldn't have gone quite as far," Powell told reporters in reference to the judgement on Iran's cooperation with the International Atomic Energy Agency (IAEA) presented earlier Monday by top EU diplomat Javier Solana.
He reaffirmed the US position that an IAEA report on Iranian compliance with the nuclear Non-Proliferation Treaty (NPT) had proved Washington's contention that Tehran had been seeking to develop atomic weapons. The assertion was not contained in the report and was apparently not shared in Europe.
"It confirms what the United States has been saying for some time -- and which we believe -- that the Iranian nuclear development program was for more than just the production of power," Powell said.
"It had an intent to produce a nuclear weapon and I think that the information that has come forward establishes that," he said after meeting at the State Department with German Foreign Minister Joschka Fischer.
Fischer, along with British Foreign Secretary Jack Straw and French Foreign Minister Dominque de Villepin, travelled to Tehran last month and won a key concession from the Iranians to stop enriching uranium.
Powell acknowledged that the trio had played a "very, very helpful role" in dealing with Iran but said the Islamic republic's history of deception about its nuclear intentions made Solana's judgement premature.
That history "should cause all of us to have serious concerns about judging too quickly whether or not we have received a full and complete story from the Iranians," he said.
Solana, speaking earlier in Brussels, said Iran had been "honest" in its nuclear dealings with the international community but stressed that it must now implement a deal to open up its nuclear sites to snap inspections.
"They have been honest. Let's see if they continue all the way to the end," he told reporters ahead of talks with Powell in the Belgian capital on Tuesday and a meeting of the IAEA governing board in Vienna on Thursday.
"We still have some hurdles to pass, but we have passed some very important ones," Solana said, adding that he did not expect the board to refer the Iranian matter to the UN Security Council, a move that could lead to sanctions.
Solana seemed to be speaking with knowlege of a draft IAEA resolution drawn up by Germany, Britain and France that would condemn Iran's past behavior but stop short of a UN referral.
Fischer, standing alongside Powell in Washington, shared Solana's general tone of optimism.
"We are quite positive about the whole atmosphere but ... we must be realists," he said, urging Iran, which adamently denies the US charges, to meet all IAEA demands for transparency and accountability.
"I think we are moving in the right direction, but we must go now into the details," Fischer said.
"It means full compliance and this must be measured by the IAEA."
Powell welcomed Fischer's call for Iranian transparency and international vigilance, but made clear that the United States had tough conditions for "realism."
"Realism means making sure that the Iranians tell us every single thing there is to know about what they have been doing with respect to nuclear development of all kinds," Powell said.