WASHINGTON (NYTIMES) - United States Secretary of State Mike Pompeo said on Thursday (June 13) that intelligence reviewed by US officials showed that Iran was responsible for attacks on two oil tankers in the Gulf of Oman, a critical waterway for the transit of much of the world's petroleum.

Mr Pompeo did not present any evidence of Iran's involvement when announcing the findings at a news conference in Washington.

The assertion is certain to fuel tensions between the Trump administration and Iranian leaders that have increased since early May, when the White House announced military movements in response to what US officials have said is a heightened threat from Iran.

Mr Pompeo said the sabotage against the two tankers was only the latest in a series of recent violent acts by Iran.

"Taken as a whole, these unprovoked attacks present a clear threat to international peace and security," he said.

The rapid escalation of tensions in early May between the US and Iran took place at about the time that four tankers were damaged by explosions at the mouth of the Persian Gulf, near the Strait of Hormuz.

The violence that occurred in the same area early on Thursday, which forced crews to abandon ship and left one vessel ablaze, was similar to the incidents from May.

Mr Pompeo and national security adviser John Bolton both said in late May that Iran was responsible for those attacks, though neither have presented evidence.

On May 30, Mr Pompeo told reporters that he had seen evidence of Iranian involvement and asserted "these were efforts by the Iranians to raise the price of crude oil throughout the world".

Details of the incidents on Thursday have remained murky, as they have for the explosions in May.

Mr Pompeo and Mr Bolton have led the Trump administration in taking a hard stand on Iran. In May 2018, President Donald Trump withdrew from a nuclear containment deal that the Obama administration and world powers reached with Iran in 2015.

The US reimposed harsh sanctions on Iran in November.

European allies have stayed in the nuclear deal and have urged Iran to do so, but President Hassan Rouhani said in May that Iran would start leaving parts of it, even though international agencies said Teheran had been abiding by all the terms until now.

Mr Trump said in recent weeks that he was open to negotiations with Iran, though he has made no real effort to start talks.

He has also said he could take military action. In late May, he announced he was sending an additional 1,500 troops to the Middle East, though that was far less than what some top administration officials had requested.

Mr Pompeo has made 12 demands of Iran that go far beyond the nuclear issues. In his talks, he has stressed the need to roll back Iran's "expansionist foreign policy" and tamp down the influence of the political and military groups in Arab nations that are supported by Iran.

From his perspective, that includes Hezbollah in Lebanon, the Houthi rebels in Yemen and a constellation of armed groups in Iraq.