Iran said it had forced a U.S. warship to turn back from entering the Strait of Hormuz on Monday, although U.S. Central Command quickly denied a report of a missile strike.

A senior Iranian official said Iran had fired a warning shot and that it was unclear whether the warship had been damaged.

Oil prices jumped 5% on renewed concerns that the vital oil route, already shut for over two months at huge cost to the global economy, would remain blocked for considerably longer, with little sign of progress towards ?a negotiated resolution of Washington¡¯s conflict with Iran.