The UAE's Minister of State for Foreign Affairs Dr Anwar Gargash hit back at Iranian claims that Yemen's Houthi rebels were acting in self-defence, after strikes on Saudi Arabia's oil facilities.
"The justification for the unprecedented terrorist attack on Aramco's facilities in view of the developments in the Yemen war is completely unacceptable," Dr Gargash said on Tuesday morning.
Dr Gargash's Twitter comments came hours after the Arab Coalition confirmed the weapons used to strike Saudi Aramco's Abqaiq oil-processing plant and the Khurais oilfield were Iranian-made.
Yemen's Iran-backed Houthi rebels claimed responsibility for the operation but Washington has squarely blamed Iran, with President Donald Trump saying the US is "locked and loaded" to respond.
The minister also urged the international community to stand behind the kingdom.
"The attack on Saudi Arabia is a dangerous escalation in itself, and the right position of every Arab country and every responsible state in the international community must be with Saudi Arabia and with the stability and security of the region," he wrote.
Shortly after the attack, the UAE Ministry of Foreign Affairs and International Co-operation denounced the attack as a "terrorist and subversive act", calling it new evidence of terrorist groups looking to undermine security and stability in the region.
"The security of the UAE and Saudi Arabia is inseparable. Any threat to the Kingdom of Saudi Arabia is seen as a threat to the stability and security of the UAE," the ministry said.
Saudi Arabia's energy infrastructure has been hit before, but this strike was of a different scale, abruptly halting half the kingdom's output – about six per cent of the world's oil supply.
However, experts say the kingdom has stocks enough to meet shortages for three months.
"All indications are that weapons used in both attacks came from Iran," rather than Yemen, Arab Coalition spokesman Turki Al Maliki told reporters in Riyadh.
The Houthis said they had fired 10 drones at the Saudi installations, and Iranian President Hassan Rouhani said: "The people of Yemen have been forced to respond – they are only defending themselves."
He was speaking at a news conference in Ankara alongside Russian President Vladimir Putin and Turkish President Recep Tayyip Erdogan.
But The New York Times reported that US officials had satellite images showing the attacks, possibly with drones and cruise missiles, had come from the north or north-west.
The images indicated they were fired from the northern Arabian Gulf, Iran or neighbouring Iraq, where Iran backs various armed groups.
US Defence Secretary Mark Esper said the US was preparing a response to the attacks.
"The United States military, with our inter-agency team, is working with our partners to address this unprecedented attack and defend the international rules-based order that is being undermined by Iran," he said in a tweet.
Shortly after, US President Donald Trump announced he would be sending his Secretary of State Mike Pompeo to Saudi Arabia.
British Prime Minister Boris Johnson on Tuesday held a phone call with German Chancellor Angela Merkel about the drone attacks.
“The Prime Minister spoke to Chancellor Angela Merkel this morning," a British government spokesperson said in a statement. “They discussed Saturday’s attacks in Saudi Arabia and the need to work together, alongside international partners, to agree a collective response."
“On the issue of Iran, they reaffirmed their commitment to a common approach and the importance of avoiding the further escalation of tensions in the region.
Martin Griffiths, the UN special envoy for Yemen, warned on Monday that attacks on Saudi Arabian oil plants at the weekend made a larger regional conflict more likely.