Qatar and the United States have agreed to a $197m sale in upgrades and other equipment for the Gulf nation's air force.

The deal announced by the US Department of State on Thursday is subject to approval from the US Congress.

"This proposed sale will contribute to the foreign policy and national security of the United States by helping to improve the security of a friendly country that has been, and continues to be, an important force for political stability and economic progress" in the Gulf region, the Defense Security Cooperation Agency said in a statement.

The US stations about 10,000 military personnel at a large base in Qatar that serves as the Air Force's Central Command headquarters for US operations in the Middle East.

The sale includes equipment that will make the Qatari air force more resistant to cybersecurity threats, it said.

Regional threats

The deal between Qatar and the US Department of State "will support the defensive capability of Qatar. The proposed sale will help strengthen Qatar's capability to counter current and future threats in the region and reduce dependence on US forces", the statement said.

Saudi Arabia, the United Arab Emirates, Egypt, and Bahrain, all US allies in the Middle East, launched a blockade against Qatar in June 2017.

The Saudi-led group alleges Qatar supports "extremism" in the region, a charge Doha has denied.

Minutes after announcing the Qatar sale on Thursday, the US State Department also approved a $270m deal to sell Sidewinder air-to-air missiles to the UAE.

It described the UAE as "a friendly country" and "an important force for political stability and economic progress in the Middle East".

There are also reports the US will sell the UAE state-of-the-art F-35 fighter jets. The US has previously sold the advanced aircraft only to Israel.

News of the US-Qatar sale came days after a military cargo plane from the UAE violated Qatari airspace, the third violation in four months.

Sources told Al Jazeera the cargo plane penetrated Qatari airspace for seven minutes on Sunday. Qatari fighter jets intercepted the plane after it failed to respond to warnings.

In January, Qatar complained to the UN about two previous UAE violations of its airspace. All Qatari aircraft are prohibited from flying inside Saudi, Bahraini, Egyptian, and UAE airspace.