"The president and the crown prince committed to close cooperation to advance our shared goals of security, stability, and prosperity across the Middle East and beyond," the White House said in a statement about their telephone talks.
"The two leaders discussed the priority of cutting off all support for terrorists and extremists, as well as how to resolve the ongoing dispute with Qatar," the statement added.
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The region is in the throes of a deep crisis.
Earlier this month, Riyadh and several of its allies including Egypt, Bahrain and the United Arab Emirates, cut ties with Qatar over accusations that Doha supports extremist groups, including some linked to Saudi foe Iran -- a claim Tehran denies.
In addition to diplomatic isolation, other measures taken included closing Qatar's only land border, banning its planes from using their airspace and barring Qatari nationals from transiting through their airports.
Qatar is home to the biggest US air base in the Middle East -- a hub in the war against the Islamic State group.
Contradictory signals
Trump's administration has sent contradictory signals on the crisis. While Trump has made statements siding with Saudi Arabia, Washington has shown mounting frustration over the kingdom's role in the crisis.
State Department spokeswoman Heather Nauert said Tuesday that the US was "mystified" that Saudi Arabia and its Gulf allies have failed to present details justifying their embargo on Qatar.
"The more that time goes by, the more doubt is raised about the actions taken by Saudi Arabia and the UAE," Nauert said.
US Secretary of State Rex Tillerson, who has been tasked by Trump to oversee an end to the crisis, has been working the phones in recent days trying to defuse a standoff that has put key US allies at loggerheads with one another.
Tillerson said Wednesday that Saudi Arabia and its allies had prepared a list of demands to be presented to Qatar.
"We hope the list of demands will soon be presented to Qatar and will be reasonable and actionable," Tillerson said in a statement.
"We support the Kuwaiti mediation effort and look forward to this matter moving toward a resolution.
On Wednesday, Saudi Arabia's King Salman ousted his nephew as crown prince and installed Mohammed, his son, as heir to the throne.
Saudi boys pose in front of a billboard showing King Salman, with his 31-year-old son Mohammed bin Salman and Prince Mohammed bin Nayef. Source: AAP
Trump, 71, and Mohammed, 31, have met twice -- once in Riyadh during the US leader's recent trip to Saudi Arabia and once in mid-March at the White House.
