U.S. government buildings, military posts and embassies will fly the flag at half-staff through Memorial Day weekend, in memory of the nearly 100,000 people who have died of COVID-19, President Trump announced Thursday night. The move comes after Democratic leaders in Congress sent a letter to the president requesting the gesture.

"I will be lowering the flags on all Federal Buildings and National Monuments to half-staff over the next three days in memory of the Americans we have lost to the CoronaVirus," Trump said via Twitter.

Flags will be lowered from Friday through Sunday's sunset. Trump added that flags will again be flown at half-staff on Monday, to honor the men and women who died while serving in the U.S. military.

The national flag is dropped to half its normal height at times when the nation is in mourning or after a national tragedy. The U.S. is currently in the throes of a pandemic that has killed around 95,000 people in the country and derailed normal life for millions of people.

"Our Nation mourns for every life lost to the coronavirus pandemic, and we share in the suffering of all those who endured pain and illness from the outbreak," Trump wrote in a proclamation ordering the observance. "Through our grief, America stands steadfast and united against the invisible enemy. May God be with the victims of this pandemic and bring aid and comfort to their families and friends."

The presidential proclamation came after House Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer sent Trump a letter asking him to order flags to be flown at half-staff on all public buildings on what they called "a sad day of reckoning" — when the U.S. marks 100,000 deaths.

"It would serve as a national expression of grief so needed by everyone in our country," they wrote.

Earlier this month, the governors of several hard-hit states ordered their public buildings to fly flags at half-staff, including New York, Massachusetts and Colorado.

The procedure for flying a U.S. flag at half-staff or at half-mast calls for it to be raised briefly to its full peak, then lowered halfway. The process is reversed when lowering the flag at the end of the day – except for Memorial Day, when the display is shortened.

"On Memorial Day the flag should be displayed at half-staff until noon only, then raised to the top of the staff," according to Title 4 of the U.S. Code regarding the flag and its protocols.

Copyright 2020 NPR. To see more, visit https://www.npr.org.