By Lefteris Papadimas and Idrees AliATHENS/WASHINGTON, July 25 (Reuters) - Air defence systems in Saudi Arabia intercepted two ballistic missiles from Yemen on Saturday targeting oil refineries in Yanbu, Greek security sources told Reuters, a day after U.S. forces launched fresh air strikes on Iran.Saudi civil defence had issued several warnings for Yanbu, on the Red Sea, and later said the danger had passed. Civil defence also issued a warning for the port city of Jizan about 1,000 km (620 miles) to the south, close to the Yemeni border.There were no immediate official reports of damage.The defence system was operated by Greek military personnel, the sources said. Greece has deployed a U.S.-made Patriot air defence battery in Saudi Arabia since 2021 under an agreement to help protect the kingdom's energy infrastructure.TRUMP THREATENS 'MAJOR PUNISHMENT' FOR IRAN AND YEMENU.S. President Donald Trump on Friday vowed "major military punishment" for Tehran and its Houthi allies in Yemen, after the Houthis said they had struck two Saudi tankers in the Red Sea on Thursday.The Houthis, who control northern and western Yemen, have declared a naval blockade of Saudi Arabia. The kingdom has been diverting millions of barrels of oil by pipeline each day to the Red Sea to skirt Iran's near-total blockade of the Strait of Hormuz on the Gulf.A Saudi-led coalition that has been fighting the Houthis in Yemen said it had struck Houthi military sites in recent days after attacks on the Saudi tankers.The U.S. military had launched air strikes on Iran late on Thursday and early on Friday, the 13th consecutive night of attacks, but there were no reports of fresh U.S. strikes on Saturday.Two weeks after the collapse of an interim truce meant to end the war, Iranian armed forces had responded by firing at U.S. bases in neighbouring Arab countries on Friday and warning that they could strike non-military buildings there used by U.S. personnel.Trump has threatened in recent days to widen the range of targets to include Iran's energy plants and bridges, send ground forces to seize its oil hub of Kharg Island, and bomb a deep-underground nuclear-linked site known as Pickaxe Mountain.On Friday, he said he had not yet made a decision on new major strikes, however. "We are talking to them," Trump told reporters at the White House. "I think they're being serious. I think ... they are being by far the most serious that we've seen them, but that doesn't mean we get there."GLOBAL OIL CHOKEPOINTSAsked what the exit strategy was for the Iran war, Trump said: "There's a military exit where we just keep going just the way we are, and we can even make it a heavier dose, and it's knocking out everything they have. Or there's a smarter strategy that you make a deal."He added: "We're locked and loaded. We're ready to go."The key waterway of the Strait of Hormuz, the entrance to the Gulf, has so far been the focus of a war that has killed thousands in almost five months, stoked global inflation and fanned fears of an economic downturn.The Houthi blockade of the Red Sea is a major escalation in the conflict that threatens to further disrupt global oil supplies. Brent North Sea oil prices jumped to $100 a barrel this week for the first time since May.Sources said Pakistan was exploring a path towards reviving stalled talks between the U.S. and Iran to end the war, after China initiated a push. Exploratory discussions took place during a visit by Iranian Interior Minister Eskandar Momeni to Islamabad this week, his second in the last 10 days, three Pakistani sources said. (Reporting by Bo Erickson, Idrees Ali, Phil Stewart and Timour Azhari; Writing by Kim Coghill; Editing by Clarence Fernandez and Kevin Liffey)