US Secretary of State Mike Pompeo made the comments while in Saudi Arabia meeting the Crown Prince (Picture: US State Department).
The US Secretary of State Mike Pompeo has described the attack on Saudi Arabian oil facilities as an "act of war".
His comments came on a visit to Saudi Arabia where he met the Saudi Crown Prince, Mohammed bin Salman.
Saudia Arabia has joined the US in blaming Iran for the weekend strikes which wiped out more than 5% of the world's oil production.
In a news conference on Wednesday, Saudi Arabia displayed what it says was weapons debris from the attack which was "unquestionably sponsored by Iran".
Houthi rebels in Yemen had claimed responsibility for the attack but the US said the pattern of destruction suggested the strikes were launched from Iraq or Iran.
Iran has denied any involvement.
According to a statement by the US Department of State, Mr Pompeo and the Saudi Crown Prince agreed the attack was "unacceptable and unprecedented".
The statement added: "The Secretary and the Crown Prince discussed the need for the international community to come together to counter the continued threat of the Iranian regime."
Meanwhile, US President Donald Trump has warned he will "substantially increase" sanctions on Iran.
Tensions have been rising between the two nations since President Trump pulled out of the 2015 nuclear deal with Iran and re-imposed sanctions.
On Wednesday, the state-run Saudi Press Agency quoted an unnamed official saying the kingdom had joined a US-led coalition to protecting shipping in the Gulf.
The UK, Australia and Bahrain are also part of the mission.
Ships from the Royal Navy are being used to escort British-flagged ships through the region as part of the coalition.
It was formed following a number of attacks on oil tankers in the Gulf's waters. The US, as well other nations, again accused Iran who denied all accusations.