The U.S. Navy stands ready to ensure freedom of navigation and free flow of commerce, a spokesman for the U.S. military’s Central Command said on Thursday, after Iran warned it will block oil shipments through the Strait of Hormuz. Iran has threatened in recent days to close the strait, a vital route for world oil supplies, if Washington tries to cut Tehran’s exports. An Iranian Revolutionary Guards commander said on Wednesday Iran would block any exports of crude for the Gulf in retaliation for hostile U.S. action. “The U.S. and its partners provide, and promote security and stability in the region,” Central Command spokesman Navy Captain Bill Urban said in an email to Reuters. Asked what would be the U.S. Naval Forces reaction if Iran blocks the Strait of Hormuz, he said: “Together, we stand ready to ensure the freedom of navigation and the free flow of commerce wherever international law allows.”The Islamic Revolutionary Guards Navy (IRGCN) lacks a strong navy and instead focuses on an asymmetric warfare capability in the Gulf. It possesses many speed boats and portable anti-ship missile launchers and can lay naval mines. A senior U.S. military leader said in 2012 the Guards have the ability to block the Strait of Hormuz “for a period of time” but the United States would take action to reopen it in such an event. In May, U.S. President Donald Trump pulled out of a multinational deal under which sanctions on Iran were lifted in return for curbs to its nuclear program. Washington has since told countries they must stop buying Iranian oil from Nov. 4 or face financial measures.