Irans supreme leader Ali Khamenei supported on Saturday President Hassan Rouhani’s call for Tehran to block Gulf oil exports if its own were stopped. Rouhani had threatened during a trip to Europe earlier this month: “It is incorrect and unwise to imagine that someday all producer countries will be able to export their surplus oil and Iran will not be able to export its oil.” "(Khamenei) said remarks by the president ... that if Irans oil is not exported, no regional countrys oil will be exported, were important remarks that reflect the policy and the approach of (Irans) system," Khameneis official website said. Iranian officials have in the past threatened to block the Strait of Hormuz, a major oil shipping route, in retaliation for any hostile US action. Khamenei used a speech to foreign ministry officials on Saturday to reject any renewed talks with the United States after President Donald Trumps decision to withdraw from a 2015 international deal over Irans nuclear program. "The word and even the signature of the Americans cannot be relied upon, so negotiations with America are of no avail," Khamenei said. It would be an "obvious mistake" to negotiate with the United States as Washington was unreliable, Khamenei added, according to his website. Irans oil exports could fall by as much as two-thirds by the end of the year because of new US sanctions.