WASHINGTON — The five permanent members of the U.N. Security Council and Germany agreed today to begin considering new sanctions on Iran after it failed to accept an incentives package meant to defuse the dispute over its nuclear program, a U.S. official said.

The decision came during a conference call between the European Union foreign policy chief, Javier Solana, and senior diplomats from the six nations that offered the incentives, according to the official, who said there was a consensus that Iran’s latest reply to the offer was “disappointing” and “appears to be a stalling tactic.”

The official, who spoke on condition of anonymity because details of the call have yet to be released by Mr. Solana’s office, said the group was now discussing next steps to take in the Security Council, including “beginning to consider the possible outlines of another sanctions resolution” against Iran.

Iran is already under three sets of U.N. sanctions. Despite the pressure 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, America, and Germany. Uranium enrichment can produce the ingredients needed to build an atomic bomb.

The official 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 Mr. Solana yesterday and was supposed to contain either an acceptance or rejection of 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.

American officials dismissed the response as unacceptable yesterday, and earlier today the French Foreign Ministry said it was insufficient.

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

America 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, a process that can produce the ingredients for a bomb.