US President Donald Trump spoke with Saudi Arabia's Crown Prince Mohammed bin Salman, media reports confirmed.

This is his first known conversation with a foreign leader since assuming office, and it comes amid a complex situation in the Middle East.

During the call, the Crown Prince congratulated Trump and conveyed the congratulations of King Salman to the President after being sworn in, wishing the American people further progress and prosperity.

The pair discussed bilateral cooperation to establish peace, security, and stability in the Middle East, in addition to enhancing bilateral cooperation to combat terrorism.

A freshly struck hostage-and-ceasefire deal is leading to hopes for greater normalisation between Israel and its neighbours.

In the call, Prince Mohammed bin Salman and Trump "discussed ways of cooperation between the Kingdom and the United States of America to establish peace, security and stability in the Middle East region, in addition to enhancing bilateral cooperation to combat terrorism," according to a statement from the Saudi official news agency.

Saudi Arabia was Trump's first stop abroad during his first presidency.

He said in the Oval Office this week that he chose the kingdom because officials there vowed to make significant investments in the United States. He said he would consider returning to Saudi Arabia if similar investments were made.

Prince Mohammed appears to have received the message.

In Wednesday's call, Prince Mohammed stressed "the Kingdom's desire to expand its investments and trade relations with the US in the next four years by an amount of $600 billion, expected to increase if additional opportunities become available".

Trump and the Saudi Crown Prince cultivated close relations during his first term, helped in part by Trump's son-in-law Jared Kushner. The warm ties came despite a US intelligence report finding Prince Mohammed played a significant role in the murder of American journalist Jamal Khashoggi.

Saudi Crown Prince Mohammed bin Salman becomes the first foreign leader to hold a phone call with US President Donald Trump since he returned to office this week for a second term.

The deal would likely be part of a massive defence agreement that Riyadh is looking to sign with Washington, which would provide Saudi Arabia with security guarantees from the US if it faces attack and be accompanied by huge investments in the American economy.

Trump told Saudi Crown Prince that he looks forward to working with Riyadh to advance common interests, the Saudi readout added.

There is no readout immediately available from the White House.