Two U.S. Navy vessels arrived in Doha to take part in a joint military exercise with the Qatari Emiri Navy on Wednesday, Qatar news agency (QNA) reported.
Qatar hosts the biggest U.S. military base in the Middle East with 11,000 troops deployed to or assigned to al Udeid Air Base. More than 100 aircraft operate from there.
The Pentagon last week renewed praise of Qatar for hosting a vital U.S. air base and for its "enduring commitment to regional security," after four Arab countries cut ties with the Gulf ally.
The Pentagon reassurance differed from the U.S. President Donald Trump comments that applauded the decision, via Twitter.
It was unclear if the arrival of the two warships was planned before the Gulf rift or if was a sign of support from the Pentagon.
The crews of the two vessels were received by Qatari navy officers, QNA said, citing a statement from the country's defense ministry.
Turkey sent its foreign minister to Qatar as part of a drive to resolve the crisis. Kuwait, a neighbor and a member of the Gulf Cooperation Council (GCC), also has been mediating.
Meanwhile, U.S. Secretary of Defense Jim Mattis and his Qatari counterpart Khalid al-Attiyah signed a letter of agreement for a $12-billion sale of 36 U.S.-manufactured F-15 fighter jets.
The drills and the jet deal come amid a political and economic blockade of Qatar by its neighbors.
Starting from June 5, Bahrain, Comoros, Egypt, Maldives, Mauritania, Saudi Arabia, United Arab Emirates, Yemen's internationally backed government and one of Libya's three governments have cut off diplomatic ties with Qatar over accusations that the Gulf nation funds militant groups – charges Doha calls baseless.
Several other Muslim nations also downgraded their diplomatic ties with Qatar.