A general view taken on June 5, 2017 shows boats sitting in the port along the corniche in Doha. 
Arab nations including Saudi Arabia and Egypt cut ties with Qatar, accusing it of supporting extremism, in the biggest diplomatic crisis to hit the region in years. / AFP PHOTO / STR        (Photo credit should read STR/AFP/Getty Images)
STR/AFP/AFP/Getty Images
A general view taken on June 5, 2017 shows boats sitting in the port along the corniche in Doha. Arab nations including Saudi Arabia and Egypt cut ties with Qatar, accusing it of supporting extremism, in the biggest diplomatic crisis to hit the region in years. / AFP PHOTO / STR (Photo credit should read STR/AFP/Getty Images)
Now playing
02:25
US officials: Russia behind Qatar crisis
Now playing
03:44
Do the 1990s hold the key to sustainable websites?
Now playing
01:10
Watch SpaceX land its Mars rocket prototype for the first time
Now playing
05:52
The climate crisis is taking these farmers' most valuable resource
U.S. President Donald Trump works on his phone during a roundtable at the State Dining Room of the White House June 18, 2020 in Washington, DC. President Trump held a roundtable discussion with Governors and small business owners on the reopening of American's small business. (Photo by Alex Wong/Getty Images)
Alex Wong/Getty Images
U.S. President Donald Trump works on his phone during a roundtable at the State Dining Room of the White House June 18, 2020 in Washington, DC. President Trump held a roundtable discussion with Governors and small business owners on the reopening of American's small business. (Photo by Alex Wong/Getty Images)
Now playing
02:37
Facebook Oversight Board: Indefinite suspension of Trump's account is 'not appropriate'
Now playing
03:41
How technology at NASA helps guide Biden on climate
Now playing
01:42
A vaccine without needles? It's on the way
SAN FRANCISCO, CA - FEBRUARY 06:  Host Conan O'Brien speaks onstage during the 5th Annual NFL Honors at Bill Graham Civic Auditorium on February 6, 2016 in San Francisco, California.  (Photo by Tim Mosenfelder/Getty Images)
Tim Mosenfelder/Getty Images
SAN FRANCISCO, CA - FEBRUARY 06: Host Conan O'Brien speaks onstage during the 5th Annual NFL Honors at Bill Graham Civic Auditorium on February 6, 2016 in San Francisco, California. (Photo by Tim Mosenfelder/Getty Images)
Now playing
01:48
Conan announces his last show after 30 years in late night
Drew Angerer/Getty Images
Now playing
03:14
Will Trump be allowed back on Facebook? This board will decide
CNN
Now playing
05:16
WTF is a SPAC?
Now playing
01:51
A shortage of tanker truck drivers could cause stations to run out of gas
CEO at Verizon Media K. Guru Gowrappan appears at the 2019 Verizon Media NewFront on April 30, 2019 in New York City.
Noam Galai/Getty Images for Verizon Media
CEO at Verizon Media K. Guru Gowrappan appears at the 2019 Verizon Media NewFront on April 30, 2019 in New York City.
Now playing
02:47
Verizon sells off Yahoo and AOL
Warren Buffett, CEO of Berkshire Hathaway, attends the 2019 annual shareholders meeting in Omaha, Nebraska, May 3, 2019. (Photo by Johannes EISELE / AFP)        (Photo credit should read JOHANNES EISELE/AFP via Getty Images)
Johannes Eisele/AFP/Getty Images
Warren Buffett, CEO of Berkshire Hathaway, attends the 2019 annual shareholders meeting in Omaha, Nebraska, May 3, 2019. (Photo by Johannes EISELE / AFP) (Photo credit should read JOHANNES EISELE/AFP via Getty Images)
Now playing
02:40
Warren Buffett warns on US inflation
Now playing
01:00
Astronauts splash down after record-setting mission
ATLANTA - APRIL 30:  A Boeing 757 with a new Delta Airlines logo sits on the tarmac following the company's emergence from bankruptcy at Hartsfield Jackson International Airport April 30,2007 in Atlanta, Georgia. The 757 sports new branding that will appear on more than 900 planes, at airports and on advertising.  (Photo by Barry Williams/Getty Images) 757
Barry Williams/Getty Images North America/Getty Images
ATLANTA - APRIL 30: A Boeing 757 with a new Delta Airlines logo sits on the tarmac following the company's emergence from bankruptcy at Hartsfield Jackson International Airport April 30,2007 in Atlanta, Georgia. The 757 sports new branding that will appear on more than 900 planes, at airports and on advertising. (Photo by Barry Williams/Getty Images) 757
Now playing
02:28
Why Delta airlines is resuming selling middle seats
Now playing
02:50
Grocery chain says 'hero pay' forcing them to close stores

Story highlights

Trump's tweeted Tuesday in praise of the Gulf nations' move against Qatar

Qatar is home to one of the largest US military bases in the region

(CNN) —  

President Donald Trump changed course on Qatar Wednesday, a day after praising a move by other Gulf nations to sever diplomatic relations with Doha, which hosts a US military base crucial to the fight against ISIS.

In a phone call with the Qatari Emir, Trump extended an olive branch, offering to help the parties resolve their differences by inviting them to a White House meeting if necessary. The outreach came as US officials told CNN they were observing increased Qatari military activity as the country placed its forces on the highest state of alert over fears of an military incursion.

Trump’s new tone echoed that of his secretaries of Defense and State, who emphasized Tuesday the need for Gulf unity and the importance of the US partnership with Qatar, home to the Al Udeid Air Base, the main regional center for air missions against ISIS.

Trump’s phone call Wednesday made for a stark contrast to a series of tweets he sent Tuesday, in which he appeared to throw his weight behind the effort by Saudi Arabia, the United Arab Emirates, Bahrain and Egypt, along with Yemen, the Maldives and Libya, to ostracize Qatar.

Referring to his May trip to the region, Trump tweeted that it was “so good to see the Saudi Arabia visit with the King and 50 countries already paying off. They said they would take a hard line on funding extremism, and all reference was pointing to Qatar. Perhaps this will be the beginning of the end to the horror of terrorism!”

In a description of the Wednesday call, the White House said Trump “emphasized the importance of all countries in the region working together to prevent the financing of terrorist organizations and stop the promotion of extremist ideology.” 

Referring to the regional group that includes Qatar, the President also “reiterated that a united Gulf Cooperation Council and a strong United States-Gulf Cooperation Council partnership are critical to defeating terrorism and promoting regional stability.” Trump spoke to the Saudi king Tuesday, the White House said, delivering a very similar message.

Trump’s belated effort to calm the situation comes as the Qatari military has brought up 16 Leopard tanks out of storage in Doha and put the military on its highest alert out of fear that Saudi Arabia and others might attempt a military incursion.

On June 5, the Qatari Ministry of Defense transmitted a message to the governments of the UAE, Saudi Arabia and Bahrain, saying they would fire on any naval ships from those countries that enter into its waters, a US official said.

That official and others say the situation in Qatar has not affected US military operations and security in the country.

The three Sunni Gulf countries – Saudi Arabia, Bahrain and the UAE – along with Egypt accuse Qatar of supporting terrorism and destabilizing the region because of its ties to their Shiite rival, Iran, and its support for groups like the Muslim Brotherhood and Hamas.

Qatar acknowledges its links to these groups, but denies that it supports terrorism.

The crisis was reportedly sparked by an interview with the Qatari leader that Qatar said was a false news story. CNN is reporting that US investigators believe Russian hackers may have been behind the effort and the FBI has been sent to Qatar to help investigate.

They have ordered Qatari citizens and diplomats out of their countries, cut all flights to Qatar and are looking for ways to bar international airlines from flying through their airspace to get to Qatar, which is slated to host to 2022 World Cup. The UAE announced Wednesday that “expressing sympathy, inclination or favoritism toward Qatar” is punishable by three to 15 years in prison, alongside a minimum fine of 500,000 dirhams, about $136,000.

Saudi Arabia has shut the only land border to Qatar, through which the country of 300,000 gets as much as 40% of its food supply, leading to empty shelves in supermarkets and fears that food and water will soon run out.