DUBAI, United Arab Emirates -- Kuwait tried to mediate a resumption of diplomatic and commercial ties between Qatar and several of its Arab neighbors Tuesday, while President Trump appeared to back those isolating the energy-rich nation over allegations it supports terror groups and Iran.

Qatar long has denied funding extremists, and its foreign minister struck a defiant tone in interviews, even after worried residents emptied grocery stores in its capital, Doha.

Qatar relies heavily on food imports, especially those coming over its only land border with Saudi Arabia, which joined with other key Arab powers Monday in cutting off land, sea and air routes into the country.

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"On this scale, it's unprecedented," said Hatoon al-Fassi, a Saudi historian of Gulf Affairs and Women's Studies at Qatar University.

CBS News has learned that Russian hackers are suspected of interfering with a news site in Qatar and may have put out fake information that helped spark the crisis. That supposed story released via a Qatari site is being blamed as a catalyst behind the regional tensions, which have been long-simmering but recently spiked in the wake of Mr. Trump's visit, CBS News' Margaret Brennan reports.

And now the biggest diplomatic crisis in the Persian Gulf since the 1991 U.S.-led war with Iraq pits several nations against Qatar, home to some 10,000 American troops and a major U.S. military base.

While the U.S. military has said it wouldn't change its posture at Qatar's Al-Udeid Air Base, Mr. Trump posted a series of tweets calling into question his commitment to the peninsular nation.

"During my recent trip to the Middle East I stated that there can no longer be funding of Radical Ideology," he tweeted. "Leaders pointed to Qatar -- look!"

During my recent trip to the Middle East I stated that there can no longer be funding of Radical Ideology. Leaders pointed to Qatar - look! — Donald J. Trump (@realDonaldTrump) June 6, 2017

He later tweeted: "Perhaps this will be the beginning of the end to the horror of terrorism!"

Secretary of State Rex Tillerson has tried to deescalate the crisis because of the troops stationed in Qatar, Brennan reports.

"We certainly would encourage the parties to sit down together and address these differences," Tillerson said.

Meanwhile, State Department spokesman Heather Nauert tried to soften Mr. Trump's comments on Qatar this week.

"They have made some progress, but they still have work to do and more needs to be done," she said.

Brennan reports that U.S. Ambassador Dana Smith praised Qatar's "great partnership" in "countering terrorist financing," as seen in a recent tweet:

#Qatar is a strong partner in combating terrorist financing and we will continue our work together. https://t.co/kddFQSD7TC — Dana Shell Smith (@AmbDana) May 31, 2017

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

In this Tuesday, Dec. 9, 2014 file photo, Qatar's Emir Sheikh Tamim bin Hamad Al-Thani attends a Gulf Cooperation Council summit in Doha, Qatar. Bahrain says it is cutting diplomatic ties to Qatar amid a deepening rift between Gulf Arab nations. AP

Sheikh Tamim bin Hamad Al Thani "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, rejecting those "trying to impose their will on Qatar or intervene in its internal affairs."

The state-run Kuwait News Agency reported that Kuwaiti ruler Sheikh Sabah Al-Ahmad Al Sabah spoke with Qatar's emir Monday evening and urged him to give a chance to efforts aimed at easing tensions. The call came after a senior Saudi royal arrived in Kuwait with a message from the Saudi king. An Omani diplomat traveled to Qatar on Monday.

Sabah left Tuesday night for Saudi Arabia, where he met with King Salman.

Russian President Vladimir Putin spoke by phone with Qatar's emirm Sheikh Tamin bin Hamad Al Thani, and reaffirmed Moscow's position "in favor of settling crisis situations by political and diplomatic means, through dialogue," the Kremlin said.

The Philippines said it will temporarily suspend the deployment of Filipino workers to Qatar. Labor Secretary Silvestre Bello said the ban took effect Tuesday, but there is no plan yet to repatriate the more than 200,000 Filipino workers in Qatar. More than 1 million Filipinos live and work in Saudi Arabia, Qatar and Bahrain.

Bahrain, Egypt and the United Arab Emirates were among those who joined Saudi Arabia on Monday in cutting diplomatic ties with Qatar. 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. Late Tuesday night, the Jordanian government announced it was reducing its level of diplomatic representation in Qatar and cancelling the local registration for Al-Jazeera TV.

Soccer's world governing body FIFA has said it remains in regular contact with Qatar, which will host the 2022 World Cup. Qatar just finished one of the stadiums for the tournament, though others have yet to be built.

Saudi Arabia, the powerhouse among those cutting ties to Qatar, said it did so due to the country's "embrace of various terrorist and sectarian groups aimed at destabilizing the region," including the Muslim Brotherhood, al Qaeda, the Islamic State of Iraq and Syria (ISIS) and militants supported by Iran in the kingdom's restive Eastern Province.

Qatar long has denied funding extremists, although Western officials have accused it 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. The countries also said they would eject Qatar's diplomats.

The nations also cut air and sea traffic with Qatar.

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 took effect Tuesday and customers are being offered a refund.

Saudi Arabia said it revoked Qatar Airways' operating licenses and closed the airline's offices in the kingdom. The Saudi ports authority said Qatari-flagged shipping vessels are barred from docking. It said it ordered shipping agents not to receive any vessels owned by Qatari companies or Qatari nationals and not to unload any goods from Qatar.

The air route between Doha 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 Airways flights already had started to be affected, with flights to Europe being rerouted through Iran and Turkey.

The number of flights in Iran's airspace has jumped from 950 a day to 1,100, Iran airports company head Rahmatollah Mahabadi told the state-run IRNA news agency. He said it was a direct result of Qatar Airways flights.