Iran ’s foreign minister warned on Thursday that any attack on his country over a drone-and-missile strike on Saudi Arabia’s oil industry will result in “all-out war,” further pushing up tensions across the Persian Gulf. The comments by Mohammad Javad Zarif represent the starkest warning offered yet by Iran in a long summer of mysterious attacks and incidents following the collapse of Iran’s nuclear deal with world powers, over a year after President Donald Trump unilaterally withdrew America from the accord. Zarif’s comments also appeared to be in response to US Secretary of State Mike Pompeo, who a day earlier while travelling to Saudi Arabia referred to the attack as an “act of war”. Asked by CNN what would be the consequence of a US or Saudi strike, Zarif said: “All-out war.” “We won’t blink to defend our territory,” he said. Met with #Saudi Crown Prince Mohammed bin Salman today to discuss the unprecedented attacks against Saudi Arabia’s oil infrastructure. The U.S. stands with #SaudiArabia and supports its right to defend itself. The Iranian regime’s threatening behavior will not be tolerated. — Secretary Pompeo (@SecPompeo) September 18, 2019 Pompeo wrote a tweet early on Thursday after his meeting with Saudi Crown Prince Mohammed bin Salman in Jeddah over Saturday’s attack on a crucial oil processing facility and oilfield. Yemen ’s Iranian-backed Houthi rebels have claimed the attack, but the US alleges Iran carried out the assault. Pompeo called the attacks “unprecedented”. “The US stands with Saudi Arabia and supports its right to defend itself,” Pompeo said. “The Iranian regime’s threatening behaviour will not be tolerated.” He did not elaborate. Trump has been non-committal on whether he would order US military retaliation. He separately said on Wednesday that he is moving to increase financial sanctions on Tehran over the attack, without elaborating. Iran is already subject to a crushing American sanctions programme targeting its crucial oil industry. Pompeo left Jeddah on Thursday heading to the United Arab Emirates to meet Abu Dhabi’s powerful crown prince, Sheikh Mohammed bin Zayed Al Nahyan. The UAE is a close ally of Saudi Arabia and joined the kingdom in its war in Yemen against the Houthis. The UAE announced on Thursday it had joined a US-led coalition to protect waterways across the Middle East after an attack on Saudi oil installations. The state-run WAM news agency quoted Salem al-Zaabi of the Emirati Foreign Ministry as saying the UAE joined the coalition to “ensure global energy security and the continued flow of energy supplies to the global economy”. Saudi Arabia joined the coalition on Wednesday. Australia, Bahrain and the United Kingdom also are taking part. Pompeo tweeted his appreciation for the UAE and Saudi Arabia joining the coalition. “Recent events underscore the importance of protecting global commerce and freedom of navigation,” he wrote. The US formed the coalition after attacks on oil tankers that American officials blame on Iran, as well as Iran’s seizure of tankers in the region. Iran denies being behind the tanker explosions, though the attacks came after Tehran threatened to stop oil exports from the Persian Gulf.