The most senior Iranian to visit Washington in 25 years said Thursday the two nations' long estrangement should be repaired through dialogue instead of threats, as world powers moved closer to imposing punishments on Iran over its disputed nuclear program.

Mohammed Khatami, a two-term Iranian president once seen as the harbinger of moderation and better relations with the United States, also said three of the nations that have offered to bargain with Iran may be willing to change the terms.

CountryWatch: Iran

Khatami said Russia, China and France would agree to negotiate without preconditions that Iran has said are unacceptable, but he did not elaborate. Those nations, with the United States, Britain and Germany, have offered trade and aid incentives to Iran if it rolls back a nuclear program that the West fears could produce a weapon, with United Nations sanctions the price of refusal.

The group agreed that Iran must shelve its uranium enrichment program before talks on the package could start and no nations have said publicly that they would reconsider.

"Even now I believe that relations between our two respective governments should be resolved through dialogue," Khatami said during a news conference with U.S. and other reporters. He spoke through a translator.

"Using violence by every side and violent language by every side is not conducive to dialogue and it will increase and exacerbate the problems," Khatami said.

He took a swipe at the Bush administration for what he called human rights abuses in the Iraq war and the pursuit of terrorists.

"I do not deny the existence of problems in Iran, but I would certainly say those are not (worse than) the violations in places like Abu Ghraib and Guantanamo," Khatami said. "Let's condemn the violation of human rights wherever it takes place."

Khatami will not meet with any U.S. officials. The trip has angered some conservatives in Congress, some influential Iranian exiles in the United States and some of the diplomats and employees held captive when Islamic fundamentalists seized the U.S. Embassy in Tehran in 1979.

Khatami is the most senior Iranian to visit the capital since that time.

President Bush and his administration are not giving Khatami a warm reception, although the U.S. government is providing and paying for a phalanx of security agents.

The administration allowed the visit to demonstrate good will toward Iranians in general, if not their leaders, and to point up the free speech and freedom of movement that are possible in the United States. Before Khatami arrived, State Department spokesman Sean McCormack said he hoped the universities and others hosting Khatami would ask him tough questions.

The centerpiece of Khatami's visit to Washington was an address Thursday at Washington National Cathedral, a few miles from the White House. About 200 protesters chanted "Shame on you" and other slogans from across the street before Khatami spoke.

The black-turbaned cleric made a scholarly, theological plea for greater dialogue among cultures but stayed away from direct commentary on current events. He did admonish both Eastern and Western cultures to "rescue life from the claws of warmongers and violence-seekers and ostentatious leaders," but he named no names.

The address coincides with what may be a turning point in the long and largely fruitless international effort to deny Iran technology and expertise that the United States claims is evidence Iran wants the bomb.

If the United States gets its way, world powers could vote in the next few weeks to impose the first in a series of punishments intended to further increase pressure on Iran.

Iran claims its program is aimed only at generating nuclear energy. The nuclear program, begun in secret nearly two decades ago, has become a point of national pride for Iran and its hard-line president, Mahmoud Ahmadinejad.

Diplomats from the countries that have offered to bargain with Tehran met Thursday in Berlin to discuss the next step now that Iran has defied a U.N. deadline to stop uranium enrichment. In different forms, enriched uranium can be used either for nuclear energy or weapons.

Khatami defended what he said is a peaceful nuclear program. He said Russia, China and France, which were part of Thursday's meeting "want negotiations without precondition ... and this is the right position."

The State Department granted Khatami a visa to visit the United States for a two-week speaking tour despite severe trade and other penalties the U.S. imposed on Iran after the 1979 revolution.

CountryWatch: Iran