WASHINGTON - The United States is revoking a general licence authorising the sale of Iranian oil, according to a US official, who also warned of consequences over Iran’s actions in the Strait of Hormuz after three tankers were hit on July 7 in the strategic waterway.After a day in which huge crowds mourned Iran’s slain Supreme Leader Ayatollah Ali Khamenei in the holy city of Qom, oil prices rose more than 3 per cent on news of the US announcement and maritime security sources told Reuters that one of the ships attacked, an LNG carrier, could be at risk of explosion.The incidents were only the latest to threaten the fragile ceasefire that the US and Iran struck in June, pausing the conflict that started in February with US and Israeli strikes across the Islamic Republic.In a potentially ma