Iran said on Saturday it would not back down "one iota" in its nuclear row with major powers, voicing defiance on the day of an informal deadline set by the West.
Western officials gave Tehran two weeks from 19 July to respond to their offer to hold off from imposing more UN sanctions on Iran if it froze any expansion of its nuclear work.
That would suggest a deadline of Saturday 2 August, but Iran, which has repeatedly ruled out curbing its nuclear activities, dismissed the idea of having two weeks to reply.
The West accuses Iran of seeking to build nuclear warheads under cover of a civilian power programme. Iran, the world's fourth-largest oil producer, denies the charge.
In a statement, President Mahmoud Ahmadinejad said that any negotiations his country takes part in are "with the view to the realisation of Iran's nuclear right, and the Iranian nation would not retreat one iota from its rights."
The United States, China, Russia, Britain, France and Germany in June offered Iran economic and other incentives to coax it into halting its most sensitive nuclear activities.
The freeze idea is aimed at getting preliminary talks started, although formal negotiations on the incentives package will not start before Iran stops enriching uranium.
In Brussels, a European Union official said Iran had so far ignored the deadline, but the bloc is ready to wait a few more days for a reply.
A White House spokeswoman said it was unfortunate the Iranians had not responded to the incentives offer: "It just further isolates their country," Dana Perino said in Washington.
Diplomats say new UN sanctions on Iran are unlikely before September and may not happen this year, though Western states may take tougher measures of their own.
Russia, one of the six powers facing Iran, has also opposed a deadline.
