Israel carried out air and missile strikes against Iran in the early hours of Friday local time, setting the stage for a major escalation in the world's largest oil producing region.
Israel said it struck military targets and infrastructure associated with Iran's nuclear program across the country. It claimed the attack was carried out in self-defense, as "Iran is closer than ever to obtaining a nuclear weapon."
The US said it was not involved in the Israeli strikes and advised Tehran not to retaliate against US personnel in the Middle East.
"Israel advised us that they believe this action was necessary for its self-defense," secretary of state Marco Rubio said, adding that the Trump administration has "taken all necessary steps to protect our forces and remain in close contact with our regional partners."
The US administration appeared to have at least advance warning of the imminent attack and on Wednesday ordered non-essential US personnel in Iraq and Israel to evacuate immediately.
Less than a day before the Israeli attack, Trump told reporters at the White House that he advised Israel against striking Iran as it may jeopardize his diplomacy with Tehran. US and Iranian diplomats were scheduled to meet on Sunday for another round of talks on a new deal to curb Tehran's nuclear program.
As long as the US and Iran are negotiating, "I don't want [Israel] going in because, I mean, that would blow it," Trump said. "Might help it actually but it also could blow it."
Iran's state news agency Irna reported explosions in and near Tehran.
WTI Nymex futures were up 8pc to $73.14/bl as of 9:30pm ET on Thursday, in after-hours trading.