Iran said Thursday that it will not retreat "one iota" on its uranium enrichment and made no concessions on this point in talks with the UN nuclear agency chief, who was trying to head off a confrontation with the Security Council. The chief, Mohamed ElBaradei, said that in four hours of talks Thursday with Iran's top nuclear negotiator, Ali Larijani, he put forward the UN demand for Iran to suspend uranium enrichment until questions over its nuclear program had been resolved. Larijani indicated suspension was not an option. "Such proposals are not very important ones," he told reporters while standing next to ElBaradei. Hours earlier, President Mahmoud Ahmadinejad had said enrichment was an Iranian red line in the talks with the United Nations.