- Vice President Mike Pence announced that Pompeo was on his way to the kingdom to "discuss our response."
- Trump called off a retaliatory US missile attack on Iran in June after the Iranians shot down a spy drone.
- The apparent hardening of the US position came as Iran's supreme leader ruled out negotiations with Washington "at any level."
US Secretary of State Mike Pompeo departed for Saudi Arabia Tuesday to discuss possible retaliation after Washington said it had proof that attacks on Saudi oil installations originated in Iran.
Vice President Mike Pence announced that Pompeo was on his way to the kingdom to "discuss our response."
"As the president said, we don't want war with anybody but the United States is prepared," Pence said in a speech in Washington.
"We're locked and loaded and we're ready to defend our interests and allies in the region, make no mistake about it," he said, echoing President Donald Trump's words on Monday.
A US official, speaking on condition of anonymity, told AFP that the Trump administration has concluded that last weekend's attack involved cruise missiles from Iran and that evidence would be presented at the UN General Assembly next week.
The apparent hardening of the US position came as Iran's supreme leader ruled out negotiations with Washington "at any level."
This appeared to nix remaining hopes for a dramatic meeting between Trump and Iranian President Hassan Rouhani at the United Nations next week.
Speaking to reporters on Air Force One over California, Trump said he too had cooled on what had always seemed to be a diplomatic longshot.
"I never rule anything out, but I prefer not meeting him," Trump said.
Yemen's Iranian-backed Huthi rebels claimed responsibility for Saturday's oil installation attacks, which halved output from the petro-state, a close ally of Washington.
But a senior US administration official cast doubt on that claim, saying that while the Huthis said they used 10 drones, one Saudi oil facility was hit "at least 17 times," and another twice by "precision-guided munitions."
Additionally, neither the type of drone "nor the cruise missiles employed in the attack can reach the facilities from Yemen. It's not possible," the official said.
WAR IN YEMEN
The Huthis are at war with Saudi-backed forces in Yemen, turning the impoverished nation into a proxy battlefield for bitter regional rivals Tehran and Riyadh.