The US President spoke to the Saudi King on Wednesday, Xinhua news agency reported.
Saudi Arabia, Bahrain, the United Arab Emirates and Egypt had cut off diplomatic ties and imposed sanctions on Qatar, accusing it of supporting terrorism.
Other countries including Libya, Yemen and the Maldives have followed suit.
Qatar strongly denied the charges against it, while rejecting a list of 13 demands put forward by the bloc for resuming diplomatic ties.
Kuwait has been trying to mediate the crisis and several top Western diplomats have toured the region to try to defuse the row, including US Secretary of States Rex Tillerson.