"I am worried (by) the report of the Agency in Vienna," Solana told reporters after the International Atomic Energy Agency (IAEA) issued its report on Wednesday.
Solana, tasked with the United States and five other world powers with presenting proposals to the Iranians to stop uranium enrichment, recalled that it is the second IAEA report to say "they are not cooperating.
"And some of the figures he offers about the quantities, the number of centrifuges, are troublesome," Solana added.
A top diplomat close to the IAEA said Iran was using some 3,800 centrifuges on November 7 and was ready to get 2,200 more working.
The IAEA in a restricted report, a copy of which was obtained by AFP, said that "contrary to the decisions of the (UN) Security Council, Iran has not suspended its enrichment-related activities."
And "as a result of the lack of cooperation by Iran in connection with the alleged studies and other associated key remaining issues of serious concern, the agency has not been able to make substantive progress," it added.
The United States has joined powers China, Russia, Britain, France and Germany in pushing for sanctions against Iran. The Security Council has imposed three sets of sanctions on Tehran over its refusal to halt uranium enrichment.
Solana said he hoped that the Obama administration will be "more engaged" in negotiations with Tehran over its nuclear program and that it take part "fully" in the negotiations with the five other powers and Iran.
For the first time during George W. Bush's administration, third-ranking diplomat William Burns joined Iran's chief negotiator Said Jalili and their counterparts from the five other powers at talks in Geneva in July.
Having long insisted that Iran suspend enrichment before meeting its nuclear envoys, officials from the Bush's administration effectively dropped their pre-conditions, analysts said at the time.
Solana, who last met Jalili in August, hoped new contacts with Iran would take place soon.
"There may be another contact in November. Not at my level. It will be below my level. My deputy and their deputy. It is not confirmed yet. It would not be a big event with publicity, it would be a discrete meeting," he said.
The top EU diplomat said he did not expect new UN Security Council sanctions against Iran before the Obama administration assumes its duties on January 20.
"From here to the new administration, I don't think there will be fundamental change on new sanctions. It does not mean that we do not continue applying sanctions," Solana said.
The major powers are trying to get Iran to suspend uranium enrichment in exchange for an offer of broad cooperation that was presented twice, once in June 2006 and then again in June this year.
Washington and its western allies charge that Tehran's nuclear program is a covert one aimed at building a bomb. Iran denies the charges, saying it is for generating electricity.
