DUBAI, UAE - A deal between the United States and Qatar for F-15 fighter jets and a visit to Doha by two US warships on Thursday showed the vital military links Washington maintains with a country now in a dispute with several other Arab nations.

Qatar remains the home of more than 10,000 US troops at a major US military base in the Middle East. So far, the dispute between Doha and nations led by Saudi Arabia has yet to shake that partnership, though cracks are showing in responses from US President Donald Trump and his administration.

Meanwhile, the United Nations agency overseeing global air travel has acknowledged receiving complaints from Qatar about other nations cutting off flying routes for its long-haul state carrier, Qatar Airways. Those cuts have seen global air travel disrupted and threatened the airline's revenues.

In Washington, Qatari Defense Minister Khalid bin Mohammed al-Attiyah met on Wednesday with US Defense Secretary Jim Mattis and signed a deal for F-15 fighter jets it described as being worth $12 billion.

"Qatar and the US have solidified their military cooperation by having fought together side by side for many years, now are in an effort to eradicate terrorism and to promote a future of dignity and prosperity," al-Attiyah said in a statement.

Bloomberg News reported the deal was for 36 jets.

The US military announced a similar $21 billion deal in November for 72 F-15QA fighter jets for Qatar in the waning days of the Obama administration. It wasn't immediately clear if the two deals were one in the same. Qatari officials did not immediately respond to questions on Thursday, though a State Department official connected the two sales.

The signing comes as Mattis has offered his support to Qatar in the past. Mattis formerly oversaw the US military's Central Command, whose forward operating base is at the vast al-Udeid Air Base in Qatar. That base serves an important role in managing the fight against the Islamic State group in Iraq and Syria, as well as war in Afghanistan.

Meanwhile, the USS Chinook, a coastal patrol ship, and US Coast Guard cutter Baranof both were in Doha on Thursday, said Commander Bill Urban of the US Navy's Bahrain-based 5th Fleet. He called the trip a "routine port visit", though Qatar's state-run news agency described the presence as being part of a "joint exercise" with the Qatari navy.

The crisis between Qatar and its Arab neighbors, all US allies, has put Washington in a delicate situation. Mattis has described Qatar as "moving in the right direction", while US Secretary of State Rex Tillerson said called for Arab Gulf nations to remain united.

Trump, meanwhile, repeatedly has accused Qatar of funding terrorist groups, one of the main allegations levied by Saudi Arabia, the United Arab Emirates, Egypt and Bahrain when they initially cut diplomatic ties on June 5.

Reuters - Ap