United States Ambassador to the United Kingdom Woody Johnson warned Americans in the United Kingdom that if they wished to return to the U.S.  to “do it now” as airlines continue to shut down services due to the coronavirus pandemic.

In a Tweet posted Wednesday Ambassador Johnson reaffirmed that Heathrow Airport, in London is still open to flights heading to the United States but that could change. As of Wednesday he said employees at the airport are ready to assist Americans trying to get home.

On Tuesday, Secretary of State Mike Pompeo told reporters he is urging Americans who are still abroad and who want to get home to do so “immediately.” He said commercial and government-chartered flights could soon stop due to the coronavirus pandemic.

“Americans who wish to return home from abroad should do so immediately and make arrangements to accomplish that,” said Pompeo.

If you are a U.S. citizen and want to fly to the U.S. do it now. Commercial flights are still available but nobody knows how long that will last. The Embassy’s Consular team and the CBP team at Heathrow do incredible work to provide services & assist in repatriating Americans! pic.twitter.com/oycSkQ1AbW

— Chargé d'Affaires Philip T. Reeker (@USAmbUK) April 1, 2020

“If you are a U.S. citizen and want to fly to the U.S. do it now,” said Ambassador Johnson. “Commercial flights are still available but nobody knows how long it will last. The Embassy’s Consular team and the CBP team at Heathrow do incredible work to provide services & assist in repatriating Americans!”

On Tuesday, British Airways announced that it will suspend all flights to and from London’s Gatwick airport amid the coronavirus pandemic, according to the BBC. The report came after EasyJet’s suspension of flights when the U.K. government warned citizens to stay put and only travel for essential needs.,

BBC reported that British Airways told its staff members that it was a challenging environment in “unprecedented circumstances.”