Iran's Supreme Leader Ayatollah Ali Khamenei joined the chorus against making concessions at nuclear talks with the major powers over the weekend.

'Nuclear technology has been achieved by our own local experts and belongs to the whole nation and no power can block us from pursuing this technology,' the Iranian leader said in a meeting with Iranian officials in Tehran.

'Our stance as well our red lines in the nuclear talks are clear and should be respected by the relevant side as a basis for the talks,' said the ayatollah, who constitutionally has the final say on all affairs of state.

President Mahmoud Ahmadinejad and other officials have already said Iran would not accept the main demand to suspend uranium enrichment, which the US and Israel fear is geared towards making nuclear weapons, a charge Tehran denies.

Iran's chief nuclear negotiator Saeid Jalili and EU foreign policy supremo Javier Solana are scheduled to meet Saturday in Geneva to discuss Iran's response to new incentives put forward by the five UN Security Council veto powers plus Germany (5+1).

Ayatollah Khamenei further warned the United States and Israel not to toy with the idea of attacking Iran's nuclear sites.

'If somebody should be so stupid and attack Iran, then our reply will be practical and very decisive - we will cut the hands off the aggressors,' Khamenei said.

Air force exercises staged by Israel last month were seen by some analysts as preparation for a possible raid on Iranian nuclear targets.