The visit by Kuwait's Emir Shaikh Sabah Al Ahmad to Washington is "historic both in the timing and the level of the accompanying delegation" and comes at a "very delicate time due to the challenges and crises in the Arab region", the Kuwaiti ambassador to the U.S. has said.
Trump "underscored the importance of all countries following through on commitments from the Riyadh Summit to maintain unity while defeating terrorism, cutting off funding for terrorist groups and combatting extremist ideology", the White House said in a statement.
Mr Trump first appeared to support Saudi Arabia in the crisis, but later came around to supporting Mr Tillerson's diplomatic efforts.
The White House said the President talked separately with the heads of state from Saudi Arabia, the UAE, and Qatar Friday.
Mr Trump griped to a group of NY and New Jersey politicians after his press conference with the Kuwaiti Emir, sources present told Politico.
The meeting will address bilateral relations and regional and worldwide developments of mutual interest, and cooperation in the fight against terror will figure high on the summit's agenda, the envoy said, stressing that Kuwait is a major partner to the United States in the war on terror. Trump applauded Kuwait's "critical contributions to regional stability". And he suggested he could help strike a quick deal. As the dispute has dragged on, the administration has dispatched other US envoys to bolster the 88-year-old Kuwaiti emir's initiative. He noted Qatar had been presented with a list of 13 demands by the other countries and was willing to discuss them. The statement, which said the countries "regret" several of the comments by Sheikh Sabah, represents an unusual rebuke in the clubby world of Gulf Arab nations.
The Saudis, along with Bahrain, the United Arab Emirates, Egypt, and other countries in the region, have broken all commercial and diplomatic ties with Qatar over its alleged financing of terrorism and close ties to regional rival Iran. Qatar hosts a US military base critical to the anti-IS fight in Iraq and Syria.