In a notice release late Monday, the State Department said that to “alleviate travel difficulties and unprecedented appointment backlogs” as a result of the global COVID-19 pandemic, the department and the Department of Homeland Security would work together to aid U.S. citizens’ return to the U.S.

“U.S. citizens currently overseas whose passports expired on or after January 1, 2020, may be able to use their expired U.S. passport for direct return travel to the United States until December 31, 2021,” the State Department said.

For more reporting from the Associated Press, see below.

The pandemic had forced the department and most embassies and consulates to close or reduce passport services.

The State Department also strongly recommended that U.S. citizens reconsider travel abroad and postpone their trips if possible. They also reminded citizens that they need proof of a negative COVID-19 test result taken within 72 hours of their flight’s departure.

“U.S. Customs and Border Protection officers will accept for admission certain expired U.S. passports, thereby assisting U.S. citizens who have been affected by appointment backlogs at embassies and consulates overseas caused by the COVID-19 pandemic,” the department said in a notice issued late Monday.

The closures resulted in waiting times of more than two months in some cases for processing passport renewals, and a significant backlog of applications remains. The department cautioned, though, that recently expired passports aren’t valid for international travel from the United States or for travel between third countries that is not directly linked to return travel to the U.S.

“Recently expired passports cannot be used to travel from the United States to an international destination or to travel to a foreign country for any length of stay longer than an airport connection en route to the United States or to a United States territory,” the department said.

It added that not all expired passports will be eligible for the waiver and urged Americans to check their status at https://travel.state.gov/content/travel/en/traveladvisories/ea/covid-19-information.html before finalizing travel arrangements.

Among the requirements are that the expired passport was originally valid for 10 years, that the passport has not been damaged or altered, and that the traveler has physical possession of it.