Two US Navy vessels arrived in Doha to take part in a joint military exercise with the Qatari Emiri Navy just days after US President Donald Trump accused Qatar of being "a funder of terrorism at a very high level".
The aircraft purchase was completed by Qatari Minister of Defence Khalid bin Mohammad Al Attiyah and his US counterpart Jim Mattis in Washington, DC, according to QNA.
The sale "will give Qatar a state-of-the-art capability and increase security cooperation and interoperability between the United States and Qatar", the defence department said in a statement.
It was unclear if the arrival of the two warships at Doha was planned before the Gulf rift or if it was a sign of support from the Pentagon.
Saudi Arabia, the United Arab Emirates (UAE), Bahrain and a number of other countries severed relations with Qatar earlier this month, accusing it of supporting armed groups and Iran - allegations Qatar has repeatedly rejected.
Riyadh also closed its border with Qatar, the only land border the emirate has. In addition, the closure of Saudi, Bahraini, and Emirati airspace to Qatar-owned flights has caused major import and travel disruptions.
The Pentagon last week renewed praise of Qatar for hosting the US airbase and for its "enduring commitment to regional security".
The Pentagon reassurance differed from Trump's comments that applauded the decision and seemed to take credit for the blackade on Qatar and the cutting of diplomatic ties.
"The nation of Qatar, unfortunately, has historically been a funder of terrorism at a very high level," Trump said earlier this month.
"We have to stop the funding of terrorism. The time had come to call on Qatar to end its funding."
Source: Al Jazeera and news agencies