Kuwait is trying to mediate a diplomatic crisis in which Arab countries have cut diplomatic ties to Qatar and moved to isolate the energy-rich, travel-hub nation from the outside world, Qatar's foreign minister said early Tuesday.

The biggest diplomatic crisis in the Persian Gulf region since the 1991 United States-led war against Iraq pits several nations against Qatar, which is home to some 10,000 American troops and a major US military base.

Airlines suspended flights and residents nervous about the peninsula's lone land border closing cleaned out grocery store shelves.

In an interview with Doha-based satellite news network Al Jazeera, Qatar Foreign Minister Sheikh Mohammed Bin Abdulrahman Al Thani said Kuwait's ruler had asked Qatar's ruling emir, Sheikh Tamim bin Hamad Al Thani, to hold off on giving a speech about the crisis late Tuesday night.

"He received a call from the emir of Kuwait asking him to postpone it in order to give time to solve the crisis," Sheikh Mohammed said.

Still, the minister struck a defiant tone, vowing his nation rejected those "trying to impose their will on Qatar or intervene in its internal affairs."

Bahrain, Egypt, Saudi Arabia and the United Arab Emirates announced Monday they would cut diplomatic ties.

Yemen's internationally-backed government, which has lost the capital and large portions of the war-torn country, also cut relations with Qatar, as did the Maldives and one of conflict-ridden Libya's competing governments.

The move came just two weeks after US President Donald Trump visited Saudi Arabia and vowed to improve ties with both Riyadh and Cairo to combat terrorism and contain Iran.

US Secretary of State Rex Tillerson said the move was rooted in longstanding differences and urged the parties to resolve them.

Soccer's governing body FIFA said it remained in regular contact with Qatar, which will host the 2022 World Cup. It did not elaborate.

Saudi Arabia said it was cutting ties due to Qatar's "embrace of various terrorist and sectarian groups aimed at destabilising the region," including the Muslim Brotherhood, Al Qaeda, the militant Islamic State group and militants supported by Iran in the kingdom's restive Eastern Province.

Egypt's Foreign Ministry accused Qatar of taking an "antagonist approach" toward Cairo and said "all attempts to stop it from supporting terrorist groups failed."

Qatar long has denied funding extremists, though Western officials have accused Qatar of allowing or even encouraging funding of Sunni extremists like Al Qaeda's branch in Syria, once known as the Nusra Front.

The Gulf countries ordered their citizens out of Qatar and gave Qataris abroad 14 days to return home to their peninsular nation, whose only land border is with Saudi Arabia.

The countries also said they would eject Qatar's diplomats.

The nations also said they planned to cut air and sea traffic.

Doha-based satellite news network Al Jazeera reported trucks carrying food had begun lining up on the Saudi side of the border, apparently stranded.

The Qatar Stock Exchange fell more than 7 per cent in trading Monday.

Qatar Airways, one of the region's major long-haul carriers, has suspended all flights to Saudi Arabia, the United Arab Emirates, Egypt and Bahrain until further notice.

On its website, the carrier said the suspension of its flights would take effect Tuesday and customers are being offered a refund.

The route between Doha, Qatar and Dubai is popular among business travelers and both are major transit hubs for travelers between Asia and Europe.

FlightRadar24, a popular airplane tracking website, said Qatar Airway flights already had started to be affected.

"Many of Qatar Airways' flights to southern Europe and Africa pass through Saudi Arabia," the site said. "Flights to Europe will most likely be rerouted through Iran and Turkey."