VIENNA, Austria – President Bush told Europeans yesterday that it was “absurd” to regard America as the greatest threat to world peace, as he concluded an American-European Union summit overshadowed by disputes on Guantanamo Bay and trans-Atlantic trade barriers.

A visibly annoyed Mr. Bush was responding to a journalist’s question about opinion polls, asking why most Europeans believe America is a greater menace than Iran or North Korea.

“It’s absurd, is my statement,” Mr. Bush snapped, taking the microphone ahead of the president of the European Commission in his haste to answer the question. “We’ll defend ourselves, but we are working with our partners to spread peace and democracy around the world.”

Even before Mr. Bush landed for the one-day meeting in Vienna, his host, the Austrian chancellor, Wolfgang Schuessel, had made clear he would be demanding the closure of the Guantanamo Bay prison camp in the name of the European Union.

As Mr. Bush arrived for the annual summit, held this year in the baroque Hofburg Palace, scattered protesters burned an American flag and chanted, “Go home, Bush.”

Once inside the meeting, however, Mr. Bush took the initiative, and spoke of his desire to close Guantanamo Bay, diplomats said. Mr. Bush said America was keen to send all but the most dangerous detainees back to their home countries.

But he pointedly reminded his European hosts that the majority of the detainees still in the camp were from countries like Saudi Arabia, Yemen, and Afghanistan.

The Bush administration previously has faced sharp criticism and opposition from Europe for proposing to send terrorist suspects to such nations, where they may face torture or the death penalty.

Speaking at the press conference after the summit, Mr. Bush said: “I’d like to end Guantanamo, I’d like it to be over with. One of those things that we will do is that we will send people back to their home countries.”

Two hundred detainees had been sent back, and some 400 remained, he went on, mostly from Saudi Arabia, Afghanistan, and Yemen. “I explained our desire to send them back. Of course, there is international pressure not to send them back. I hope we will be able to resolve that,” he said.

The president repeated his insistence that some of those in the camp were “cold-blooded killers” who had to be tried in American courts and who would murder again if let out on the streets.

Mr. Bush was starting the summit when he and his European hosts learned of a statement from the Iranian president, Mahmoud Ahmadinejad, declaring it would be mid-August before his country responded to a European offer of incentives to suspend suspicious nuclear enrichment activities.

Asked if America would participate in provisional talks while waiting for a final Iranian verdict, Mr. Bush replied, “Our position is, we’ll come to the table when they verifiably suspend. Period.”

The president said two months “seems like an awfully long time” to wait for an answer to the European offer, presented in early June. “It shouldn’t take the Iranians that long to analyze what’s a reasonable deal.”

Mr. Bush also offered a warning to North Korea that it faced further isolation if it carried through on hints that it was about to test-fire a long-range missile, capable of hitting Alaska.

Mr. Bush was tackled a second time on the collapse in European public support for his administration by a Viennese journalist who reeled off statistics, including the fact that three-quarters of Austrians regard America as a grave threat.

It is absurd to think America is more dangerous than Iran, he repeated. “We are a transparent democracy, we debate things in the open,” he said.

Citing record American funding for AIDS victims in Africa, Mr. Bush said his foreign policy was “tough when it has to be, but on the other hand it’s compassionate.”

On trade barriers, the two sides appeared to have made little progress, with only weeks to go until a crucial meeting to agree on market-opening measures aimed at helping the developing world.

A formal joint statement said only that the European Union and America were committed to “reaching an ambitious conclusion” to the current round of talks, which have already missed crucial deadlines and are far behind schedule. It offered no specifics.