The top lawmakers on the House Foreign Affairs Committee urged the CEOs of three domestic airlines to do more to help the State Department bring home Americans stranded abroad because of the coronavirus pandemic.

In a letter, House Foreign Affairs Committee Chairman Eliot Engel Eliot Lance EngelThe Hill's Morning Report - Sponsored by The Air Line Pilots Association - Pence lauds Harris as 'experienced debater'; Trump, Biden diverge over debate prep Coons beats back progressive Senate primary challenger in Delaware Overnight Defense: Trump hosts Israel, UAE, Bahrain for historic signing l Air Force reveals it secretly built and flew new fighter jet l Coronavirus creates delay in Pentagon research for alternative to 'forever chemicals' MORE (D-N.Y.) and ranking member Michael McCaul Michael Thomas McCaulRussia continues Navalny probe, wants to send additional investigators to Germany Pompeo says 'substantial chance' Navalny poisoning was ordered by senior Russian official House panel calls for Trump to investigate Russia's role in Navalny poisoning MORE (R-Texas) urged American Airlines, Delta Air Lines and United Airlines to “participate to the fullest extent possible” in ongoing repatriation efforts.

The lawmakers noted that repatriation requests from Americans overseas are increasingly occurring in remote and hard-to-reach places and asked the airlines for help.

“As the possibility remains of additional border closures or travel restrictions around the world," the lawmakers wrote, "there is still much work to be done.”

“And as Americans’ requests for repatriation assistance come from increasingly distant locales with complex flight logistical requirements, our constituents will need the support of America’s airline industry leaders to help ensure that all Americans are able to make it home.”

Tens of thousands of Americans remain stranded abroad amid unprecedented border closures around the world as countries try to stem the spread of COVID-19.

The State Department has helped more than 46,000 Americans return from approximately 81 countries, with repatriation efforts ongoing.

In a shift of its strategy to speed up repatriation efforts, the department is working to have foreign governments allow U.S. airlines to reestablish international routes specifically for stranded Americans, and in some cases create new routes for airlines that don’t typically serve such locations.

“We’re looking to enhance the airline industry’s ability to go back into these places,” Ian Brownlee, the head of the State Department’s repatriation task force, said in a briefing with reporters on Tuesday.

“What’s a bit more complicated is getting the necessary permissions at the other end, and this is particularly the case where some of these carriers had not previously served those destinations.”

The number of Americans requesting repatriation flights is highly fluid as countries end commercial travel options on short notice. The State Department said its repatriation efforts are shifting toward South and Central Asia and Africa after weeks of focusing on South and Central America.