The statement came as U.S. Secretary of State Rex Tillerson and British National Security Advisor Mark Sedwill visited Kuwait, which is acting as a mediator, in order to patch up the row among the Western-allied countries.
Coming from some of the most influential powers in the dispute, the plea for a negotiated solution may aim at an earlier refusal by Qatar's adversaries to discuss renewing ties with Doha until it first acquiesced to a list of stiff demands.
Saudi Arabia, Bahrain, UAE and Egypt imposed sanctions last month, accusing Doha of aiding terrorism, something it denies.
The State Department said Tillerson would hold talks with leaders in Kuwait, Qatar and Saudi Arabia.
Riyadh and its allies accuse Qatar of financing extremist groups and allying with Iran, the Gulf Arab states' arch-foe.
Qatar denies that it supports militant organisations and says the boycott is part of a campaign to rein in Qatar's independent foreign policy.
The United States worries the crisis could affect its military and counter-terrorism operations and increase the regional influence of Tehran, which has been supporting Qatar by allowing it to use air and sea links through its territory.
Qatar hosts Udeid Air Base, the largest U.S. military facility in the Middle East, from which U.S.-led coalition aircraft stage sorties against ISIS in Syria and Iraq.
U.S. President Donald Trump has expressed support for Saudi Arabia in the dispute.