US Secretary of State Rex Tillerson is expected to arrive in Kuwait on Monday to help seek a resolution to the crisis between Qatar and four Arab states.
Tillerson will "meet with senior Kuwait officials to discuss the ongoing efforts to resolve the Gulf dispute", the state department said in a statement.
His presence in the region leaves open the possibility that he may try to shuttle between the neighbouring countries to forge a resolution to the dispute.
Saudi Arabia, the United Arab Emirates, Bahrain and Egypt cut ties with Qatar on June 5 and imposed a land, air and sea blockade on the country.
The quartet accuse Qatar of funding "terrorism", an accusation Qatar rejects as "baseless".
On June 22, they issued a 13-point list of demands, including the shutdown of Al Jazeera, as a prerequisite to lift the sanctions.
Doha rejected the demands and the countries now consider the list "null and void".
But the Gulf state of Kuwait is still trying to mediate the dispute.
The US has been supporting Kuwait's mediation efforts, but Tillerson's trip will mark a new level of US involvement.
On Thursday, the state department warned the crisis could potentially drag on for week or even months and "possibly even intensify".
"We've become increasingly concerned that that dispute is at an impasse at this point. We believe that this could potentially drag on for weeks; it could drag on for months; it could possibly even intensify," state department spokeswoman Heather Nauert said.
She didn't specify what type of escalation the US fears. But she said Tillerson has been in close contact with the countries involved.
Last month, Tillerson urged the Saudi-led group to ease their blockade on Qatar, saying it is causing unintended humanitarian consequences and affecting the US-led fight against the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group.
"Our expectation is that these countries will immediately take steps to de-escalate the situation and put forth a good faith effort to resolve their grievances they have with each other," Tillerson said.
More than 11,000 US and coalition forces are stationed at the Al Udeid Air Base in Qatar, from which more than 100 aircraft operate.
