The latest approval marks another windfall for plane maker Boeing and other large US defence manufacturers, although it may face opposition from critics of Saudi Arabia and the United Arab Emirates' controversial role in Yemen's ongoing civil war.

Among the biggest agreement announced by the US State Department was for the $3.51 billion sale to the Saudi kingdom - which is leading the coalition in Yemen - of 48 CH-47F Chinook cargo helicopters with spare engines and machine guns.

Boeing and Honeywell Aerospace will be the main contractors, while up to 60 Americans - both private and government employees - will work in Saudi Arabia to maintain the aircraft.

Meanwhile, the United Arab Emirates spent $3.5 billion on 27 AH-64E Apache attack helicopters plus support equipment, made by Boeing and Lockheed Martin.

Qatar has requested eight C-17 military cargo jets and spare engines in a pair of contracts totalling $781 million.

Washington also approved a contract to sell Morocco 1,200 TOW 2A anti-tank missiles made by US arms giant Raytheon for $108 million.

Although the State Department has approved the sales, after consultation with the Pentagon, Congress could still block them in theory due to widespread criticism of the Saudi-led coalition war on Yemen which has killed more than 10,000 since it began.

All four Arab countries involved are US allies and have made major arms purchases in the past, meaning the contracts are expected to be approved without problem.