The United States on Tuesday revoked a 60-day sanctions waiver that had allowed the sale of Iranian oil, according to the Treasury Department. The license, issued last month as part of an interim agreement to halt fighting between the US and Iran, had temporarily eased restrictions on Iranian oil exports. Treasury officials did not immediately explain why the waiver was withdrawn.The move came hours after the British military said three tankers were struck by projectiles in the Strait of Hormuz, the latest attacks on vessels transiting the strategic waterway at the centre of efforts to secure a permanent end to the conflict between Washington and Tehran.(This is a developing story)