Israel's defense minister Ehud Barak has called for increased sanctions on Iran, a day after the United States said Tehran is feeling the pressure of international measures meant to push it to stop enriching uranium.
Barak said Thursday after meeting his Japanese counterpart in Tokyo that while current sanctions are affecting Iranian officials, more action is necessary.
"I think that the sanctions should be ratcheted up and made even more urgent," he said. "I think that for the first time we see certain signs of impact of these sanctions, but they might not suffice to compel the Iranian leadership to take decisions. So we feel that there is still a need for more effective and paralyzing sanctions on Iran."
The United States on Wednesday downplayed Iran's claims of advances in its nuclear program, saying Tehran wants to distract from its growing diplomatic isolation.
Iran said it had installed a new generation of centrifuges to enrich uranium, and for the first time loaded domestically produced nuclear fuel into Tehran's research reactor.
U.S. State Department spokeswoman Victoria Nuland dismissed the announcements as "hype."
"We frankly don't see a lot new here. This is not big news. It seems to have been hyped," she said. "The Iranians have, for many months, been putting out calendars of accomplishments, and based on their own calendars, they are many, many months behind. This strikes us as calibrated mostly for a domestic audience."
Israel and Western powers suspect Iran is trying to speed up enrichment of uranium to the higher purity to develop nuclear weapons. Iran says its enrichment activities are aimed at producing fuel for power plants and medical research.
Nuland says Iran must show its nuclear program is for civilian purposes.
"They still need to demonstrate to all of us, including taking advantage of the IAEA inspection team now, that this is a purely peaceful program as they claim," she said.
Iran hailed the advances as a step toward mastering the complete nuclear fuel cycle, despite U.N. and Western sanctions aimed at stopping the process. White House spokesman Jay Carney said Iran is making "defiant" statements because its leadership and economy are under "enormous pressure" from sanctions.
Israel and its chief ally the United States refuse to rule out military action to prevent Iran from building a nuclear weapon. Israel sees an Iranian atomic bomb as a threat to its existence.
Russia's deputy foreign minister, Sergei Ryabkov, said Wednesday that a nuclear-armed Iran is "not an option for Russia," voicing concern at progress made by Tehran in its nuclear drive. But, the Russian official also said sanctions have had little effect, and called on world powers to hold "serious negotiations" with Iran to resolve the nuclear dispute.
The European Union said Wednesday it received a formal Iranian reply to a letter sent almost four months ago offering Iran a resumption of nuclear talks with the five permanent U.N. Security Council members plus Germany - a group known as P5+1. The Iranians said they are ready for "dialogue" and "cooperation."
EU officials said they were studying the Iranian response carefully and consulting with other members of the group. The parties last met in Istanbul a year ago but made no progress.
In a separate development, Iran's oil ministry said Wednesday Tehran has not stopped exporting crude to EU nations. Earlier, some Iranian state news agencies said Iran was cutting off exports to six EU nations in retaliation for an impending EU boycott of Iranian oil.
Some information for this report was provided by AP, AFP and Reuters.