Ali Larijani travelled to China from Russia, where talks were "positive"

Beijing has said it favours diplomacy over the threat of sanctions - which it has the power to veto at the UN.

Washington and the European Union fear Tehran aims to develop nuclear weapons, which Iran has consistently denied.

UN Secretary General Kofi Annan has said he doubts the UN nuclear watchdog will be able to decide next month whether to refer Iran to the council.

The UN's International Atomic Energy Agency (IAEA) is due to hold an emergency meeting over Iran on 2 February in Vienna.

Foreign ministers of the five permanent members of the Security Council plus Germany will meet in London early next week to discuss their strategy ahead of the talks.

IRAN'S NUCLEAR STANDOFF Sept 2002: Work begins on Iran's first reactor at Bushehr Dec 2002: Satellites reveal Arak and Natanz sites, triggering IAEA inspections Nov 2003: Iran suspends uranium enrichment and allows tougher inspections June 2004: IAEA rebukes Iran for not fully co-operating Nov 2004: Iran suspends enrichment under deal with EU Aug 2005: Iran rejects EU plan and re-opens Isfahan plant Jan 2006: Iran re-opens Natanz facility

Iran warned on Wednesday it would begin enriching uranium if it was referred to the Security Council for sanctions.

Mr Larijani will hold talks with top Chinese officials during his day-long visit, Iranian officials said.

He travelled to China from Russia, where he met senior officials in Moscow on Tuesday.

Mr Larijani said he was positive about a compromise solution put forward by Russia which would allow Iran to enrich uranium on its soil.

US Deputy Secretary of State Robert Zoellick, who is also visiting China this week, said he had warned Chinese leaders that allowing Iran to develop nuclear weapons could threaten supplies of oil from the Middle East, the Associated Press news agency reports.