Six nations agreed Wednesday to pursue new U.N. sanctions against Iran after it failed to accept incentives offered in hopes of defusing the dispute over its nuclear program, the United States said.

The decision came in a conference call between senior diplomats from the five permanent members of the U.N. Security Council and Germany with European Union foreign policy chief Javier Solana, the State Department said.

Spokesman Gonzalo Gallegos said there was consensus in the group that Iran's latest reply to the offer was "very disappointing" and "a stalling tactic" that had left the group with no option other than to seek new sanctions.

"We are very disappointed that Iran has yet again failed to give Javier Solana a clear answer to the ... generous incentives package," he told reporters. "We agreed that we have no choice but to pursue further measures against Iran."

"Given the absence of a clear, positive response from Iran, (the six countries) are discussing next steps in the U.N. Security Council and beginning to consider the possible outlines of another resolution," Gallegos said.

The council has already passed three sanctions resolutions against Iran. Despite that pressure and the threat of a fourth, it has yet to agree to stop enriching uranium in exchange for economic and other incentives being offered by the six countries: Britain, China, France, Russia, the United States and Germany. Uranium enrichment can produce the ingredients needed to build an atomic bomb.

Gallegos said the incentives were still on the table but stressed that participants in the conference call had been displeased by Iran's latest response to the offer, a one-page document which was submitted to Solana on Tuesday and was supposed to contain either an acceptance or rejection of negotiations over the package.

Instead, the response repeated Iran's long-standing position that it has a right to peaceful nuclear activities and said it would not give a definitive answer to the offer until its own questions about it had been answered.

"The letter that we received yesterday appears to be a stalling tactic," Gallegos said.

White House press secretary Dana Perino said Wednesday that the response was not "a decent and responsive statement from the Iranians." She told reporters aboard Air Force One as President Bush flew from South Korea to Thailand as part of an Asian tour that "the Iranians have long stalled on responding to the allies."

Also Wednesday, the French Foreign Ministry said the response was insufficient.

France regrets that Iran "has again chosen not to provide a clear response," Foreign Ministry spokesman Romain Nadal said in Paris.

The United States and others accuse Iran of trying to develop nuclear weapons under cover of a civilian atomic energy program. Iran denies the charge, insisting its program is peaceful, but it has thus far refused to halt enriching uranium.

The incentives were presented to Iran earlier this year and reiterated on July 19, when senior diplomats from the six nations and the European Union met in person with Iran's chief nuclear negotiator Saeed Jalili and set an informal two-week deadline for Iran to respond.

That meeting was notable because the Bush administration broke with its long-standing policy and sent the State Department's third-ranking diplomat to the session intended to prove its seriousness about the package.

Amid Wednesday's flurry of diplomatic activity, the U.N. nuclear watchdog, the International Atomic Energy Agency, said one of its top officials would travel to Iran on Thursday. It was not immediately clear if the incentives package would be on deputy IAEA director general Olli Heinonen's agenda for talks with the Iranians.