Prime Minister Gordon Brown warned Iran on Monday it faced growing isolation if it rejected an offer from major powers on its disputed nuclear programme.
In the first address to Israel's parliament, the Knesset, by a British prime minister, Brown pledged to stand by Israel and said Iranian President Mahmoud Ahmadinejad's threats to wipe the country off the map were "totally abhorrent".
"Iran has a clear choice to make: suspend its nuclear programme and accept our offer of negotiations or face growing isolation and the collective response not just of one nation but of all nations around the world," Brown said.
He said Britain, which as a permanent member of the U.N. Security Council has helped push through three sanctions resolutions against Iran, "will continue to lead . in our determination to prevent an Iranian nuclear weapons programme".
The United States, Britain, France, Germany, Russia and China have offered Iran financial and diplomatic incentives to halt nuclear activity which the West fears is a cover for making bombs. Tehran says it is aimed solely at generating electricity.
After talks in Geneva ended in stalemate on Saturday, the six major powers gave Iran two weeks to answer calls to rein in its nuclear activities or face tougher sanctions.
Government officials with Brown said if Iran did not accept the incentives, the next step would be to ratchet up sanctions, possibly including sanctions on the oil and gas industry.
They said such sanctions could seek to target Iran's domestic energy market by making it difficult for Iran to obtain equipment and spare parts for its refineries.
Tensions between Iran and the West have helped drive up crude oil prices to record highs in recent months.
