Germany, Britain, and France had led negotiations for the European Union with Iran, promising incentives if Tehran ceased uranium enrichment. France today expressed "concern" at the Iranian move.
Iranian officials say the EU failed to respond to Tehran's proposals to solve the impasse in time.
IAEA Director-General Mohammad el-Baradei urged Iran to refrain from unilaterally moving ahead on sensitive nuclear activities and instead to continue negotiations.
Russia, which is helping Iran build the nuclear power plant at Bushehr, today called on Iran not to resume its uranium-enrichment program.
The United States has repeatedly accused Tehran of seeking to develop nuclear weapons, a charge that Iranian officials have denied.
White House spokesman Scott McClellan warned Iran today against restarting its nuclear activities, saying such an action could lead to the U.S. and its European allies seeking UN action against Tehran.
Recent news on Iran:
"Tehran Issues New Nuclear Deadline"
"Iran Vows To Resume Nuclear Work"