US President Joe Biden hosted Qatar's emir Monday in the White House, underscoring the tiny Gulf state's strategic importance -- including in a scramble to shield European allies from potential Russian energy cut-offs.

Minutes after Boeing and Qatar Airways concluded a huge new deal, Biden lavished praise on Sheikh Tamim bin Hamad al-Thani, saying "our partnership in Qatar has been central to many of our most vital interests."

"A lot on our agenda today, " Biden said in the fireside Oval Office sit-down.

"We want to talk about security in the Gulf and the broader Middle East, ensuring the stability of global energy supplies, continuing our work together to support the people of Afghanistan, and strengthening commercial cooperation."

On that last note, the two leaders were able to celebrate a $20 billion deal for Qatar Airways to become the first customer for Boeing's new 777x cargo planes, with 34 aircraft in the initial order.

In a White House ceremony, Qatar Airways likewise signed a letter of intent for $6.7 billion for 25 737 MAX narrow-body airliners.

Recognizing Qatar's place in the US military's global footprint -- the state hosts the Pentagon's Central Command and a huge airbase -- Biden also announced he was designating it a "major non-NATO ally," which opens the door to closer military and commercial ties.

Overshadowing the meeting, however, were efforts to source enough natural gas to keep Europe heated through the winter if the brewing conflict with Russia escalates.

Western capitals are threatening unprecedented economic sanctions if Russia attacks Ukraine, where it has placed more than 100,000 combat troops on the borders.

However, there are fears that the oil- and gas-producing giant could then retaliate against the European Union, which imports some 40 percent of its natural gas from Russia and is already going through a steep price crunch.

The emir was the first Gulf state leader to visit Biden since he became president just over a year ago.

Qatar's Emir Sheikh Tamim bin Hamad al-Thani (L) meets Tunisia's President Kais Saied in the Tunisian capital on February 24
Qatar's Emir Sheikh Tamim bin Hamad al-Thani (L) meets Tunisia's President Kais Saied in the Tunisian capital on February 24 AFP / Fethi Belaid

In addition to meeting Biden, the sheikh was meeting with Defense Secretary Lloyd Austin, Secretary of State Antony Blinken, members of Congress and other officials.

During the Afghanistan evacuation last year, US forces sent about 60,000 Afghans and Americans transiting through the Qatar air base.

Doha served as Washington's diplomatic contact with the Taliban, through months of painful negotiations, and will be pivotal to any future contact with Afghanistan, as well as playing a role in efforts to resurrect the Iran nuclear deal.

Biden described Qatar as "a good friend and a reliable partner."

Given Qatar's energy riches, it now finds itself rising in importance on yet another front now -- the transatlantic tensions over Russia's intentions in Ukraine.

Qatar is one of the world's biggest liquid natural gas exporters, along with the United States and Australia, and there are hopes in Washington and Europe that Doha can temporarily redirect exports destined for Asian markets.

However, Qatar has little to no extra capacity in its LNG and there are limitations to how much supply can be diverted from existing contracts.

Speaking just ahead of the visit, a senior US official seemed to downplay the focus on how much to expect from Qatar in the energy reshuffle, saying only "we're consulting with all the leading gas suppliers around the world."

"I'm not going to be able to give you anything further on LNG," the official told reporters Sunday, speaking on condition of anonymity. "It will figure in the mix, but I can't give you any details."