Oil rose to $64 on Tuesday after Iran, the world's fourth biggest crude exporter, jangled investor nerves by breaking U.N. seals at nuclear power plants. Branded a "step in the wrong direction" by the European Union, the move is apt to intensify calls for Tehran to be sent to the United Nations Security Council for possible sanctions Oil is $5 a barrel higher since late December, even after a retreat on Monday, driven by renewed tension in the Middle East and a rush of investor money. U.S. crude gained 55 cents to $64.05 a barrel by 1230 GMT. Prices hit a peak of $64.61 on Monday, their highest since October 12, before easing. London Brent crude rose 35 cents to $62.36. Analysts said they could see no easy solution to the Iranian situation, raising the risk of supply disruption from OPEC's second biggest producer. "It is something everybody should be concerned about," said Craig Pennington of Schroders. "Definitely." In Israel, Prime Minister Ariel Sharon was in a critical but stable condition as doctors tried to rouse him from a coma. Analysts fear the loss of the 77-year-old could deepen uncertainties over talks with the Palestinians, stirring tensions across the oil-rich region.