Iran launched an apparent surprise attack against US bases across the Middle East at 21:45 GMT on Tuesday, according to the US Central Command (Centcom).
The US military intercepted all incoming missiles launched by Iran's Islamic Revolutionary Guards Corps, said Centcom, which oversees the Middle East-based US forces. Official Iranian sources did not immediately confirm the attack or provide an explanation.
US and Iranian forces had refrained from attacking each other since 24 July, following 13 consecutive days of attacks. President Donald Trump's administration said it was pursuing some form of diplomacy with Iran, but the parties' public statements continue to highlight disagreement over the strait of Hormuz and other issues.
Iran until now reacted to US strikes, rather than launching preemptive attacks. It was not clear what caused an apparent change in Iranian tactics.
A pause in fighting from 24-27 July helped push oil futures lower, and September Nymex WTI settled at $79.26/bl on Tuesday. But vessel traffic through the strait of Hormuz remains constrained and Yemen's Houthi militant group appears to have started targeting Saudi oil shipping in the Red Sea.
Trump met with Israeli prime minister Benjamin Netanyahu in Washington on Tuesday, with both describing their meeting as productive but providing few other details.
Iranian and Ukrainian foreign ministers held a telephone conversation on Tuesday to address a Ukrainian missile strike against an Iranian commercial vessel in the Caspian sea. Tehran and Kyiv said they are not looking to escalate conflict, and Iranian foreign minister Abbas Araghchi said he asked for compensation for the loss of crew and damage to the Iranian ship.
