Five veto-wielding members of the UN Security Council, the United States, Britain, France, Germany, China and Russia, discussed on Tuesday a draft resolution expanding sanctions against Iran.

"Sanctions against Iran do not mean the negotiation process has come to an end," said Mikhail Margelov, who heads the Russian upper house's international relations committee.

The measures foresee the expansion of the existing arms embargo to include more types of heavy weapons and introduce a ban on Iranian bank operations abroad and allow the inspection of Iranian ships by international experts.

Iran's Bushehr nuclear power plant will go into operation by the end of the summer, the head of the Russian Federal Atomic Energy Agency (Rosatom), Sergei Kiriyenko, said last week.

The launch date for Bushehr has been postponed many times for financial and technical reasons. Iranian officials have claimed that Russia was reluctant to finish the facility due to UN sanctions and concerns voiced by world powers that the plant is part of a covert nuclear weapons program.

Russian President Dmitry Medvedev said earlier sanctions, if imposed, were unlikely to target Iran's energy sector or its international trade.

Tuesday's discussion on the new UN resolution draft follows the signing by the Iranian, Brazilian, and Turkish foreign ministers on Monday of an agreement on the exchange of low-enriched uranium to fuel Tehran's scientific research reactor.

Tehran agreed to swap in Turkey most of its 3.5%-enriched uranium for 20%-enriched fuel. Some experts believe this will allow the Islamic Republic to get several nuclear charges.

"Russia, the United States and China obviously agreed with this opinion and managed to approve the UN Security Council resolution on sanctions against Iran," Margelov said.

The situation around the Iranian nuclear issue escalated on February 11 when President Mahmoud Ahmadinejad announced that Tehran produced its first batch of uranium enriched to a level of 20% and has more potential to enrich uranium.