World oil prices struck the highest points so far in 2007, nearing 64 dollars a barrel in London on Monday as the market fretted over rising tensions in major crude producer Iran, traders said.

In London, the price of Brent North Sea crude May delivery rose 52 cents to 63.70 dollars a barrel in electronic deals. It had earlier struck 63.97 dollars -- the highest point since December 6.

New York's main oil futures contract, light sweet crude for delivery in May, gained 45 cents to 62.73 dollars in electronic deals ahead of the official US open. It earlier reached 62.96 dollars -- last seen on December 21.

The Iran situation is adding a "geopolitical risk premium to crude prices, with many market participants concerned that the (nuclear) situation could escalate, potentially leading to Iran using oil as a bargaining tool," Sucden analyst Michael Davies said in London.

Iran, the world's fourth-biggest producer of oil, said Sunday it would restrict its cooperation with the UN nuclear watchdog in retaliation for fresh Security Council sanctions over its disputed atomic programme.

The United Nations Security Council voted unanimously Saturday to impose the sanctions in a bid to pressure Iran into freezing its uranium enrichment programme.

The decision followed word on Friday that Iran had seized 15 British sailors in the Gulf, a move which roiled the market.

On Monday Russia's deputy foreign minister said the new UN sanctions imposed on Iran are "reversible."

The sanctions passed "are another signal to the Iranian government and we would hope that they would understand it correctly," the Itar-Tass news agency quoted Sergei Kisliak as saying.

"All sanctions are reversible and it is still possible to resolve the Iranian question through political means," the deputy minister added.

Meanwhile the British navy personnel seized by Iran are being interrogated and will have to answer to allegations they violated Iranian waters, an Iranian official said on Monday.

"The case of the Britons who violated Iranian territorial waters is following the due legal process and they must answer for their violation," deputy foreign minister Mehdi Mostafavi said, state television reported.