Saudi Crown Prince Mohammed bin Salman has accused Iran of attacks on two oil tankers in a vital Gulf shipping channel, adding he "won't hesitate" to tackle any threats to the kingdom.

"The Iranian regime did not respect the presence of the Japanese prime minister as a guest in Tehran and responded to his (diplomatic) efforts by attacking two tankers, one of which was Japanese," Prince Mohammed told pan-Arab daily Asharq al-Awsat, referring to the attacks in the Gulf of Oman on Thursday.

"We do not want a war in the region... But we won't hesitate to deal with any threat to our people, our sovereignty, our territorial integrity and our vital interests," he added.

The twin attacks sent crude prices soaring amid a tense standoff between Iran and the US.

The Japanese-owned Kokuka Courageous was carrying highly flammable methanol through the Gulf of Oman when it was rocked by explosions, causing a blaze that was quickly extinguished.

A tanker owned by Oslo-listed company Frontline was also targeted.

The two vessels were attacked around the time Japanese Prime Minister Shinzo Abe was meeting with Iranian leaders in Tehran

US President Donald Trump said the attacks had Iran "written all over it".

Tehran has vehemently denied any involvement.

Saudi Arabia, a close US ally, is a bitter regional rival of Iran.

Iran has repeatedly warned in the past that it could block the strategic Hormuz Strait in a relatively low-tech, high-impact countermeasure to any attack by the United States.

Doing so would disrupt oil tankers travelling out of the Gulf region to the Indian Ocean and global export routes.