US officials pressed their case Tuesday for sanctioning Iran because of its nuclear defiance before a tentative EU-Iranian meeting billed as a last-ditch effort to persuade the Islamic republic to freeze uranium enrichment. US officials on both sides of the Atlantic suggested that the time had come for sanctions even before that meeting, tentatively set for Vienna on Wednesday. Their comments reflected Washington's skepticism that Tehran would change course in talks with Solana and signal readiness to head a Security Council demand to freeze enrichment, a potential pathway to nuclear arms. "There is going to be some work that's required in the Security Council," State Department spokesman Sean McCormack said in Washington. "I would expect that that is going to be tough, intensive diplomacy over the course of the coming weeks."