President Trump announced Monday he ordered the American flag to fly at half-staff through this coming Sunday to honor the late Sen. John McCain.

"Despite our differences on policy and politics, I respect Senator John McCain’s service to our country and, in his honor, have signed a proclamation to fly the flag of the United States at half-staff until the day of his interment," said Trump, who added that Vice President Mike Pence would make remarks at Friday's ceremony honoring McCain at the U.S. Capitol.

McCain will lie in state at the Capitol on Friday, officials have said. A memorial service will be held at the National Cathedral in Washington the following day before McCain is laid to rest at the U.S. Naval Academy Cemetery in Annapolis, Md., on Sunday.

Trump said White House Chief of Staff John Kelly, Defense Secretary James Mattis and National Security Adviser John Bolton would represent the administration at the services.

The president made his first public comment on McCain's death Monday night at a dinner with evangelical leaders at the White House.

"Our hearts and prayers are going to the family of Sen. John McCain," Trump said. "We appreciate everything McCain has done for our country."

Trump's initial statement was made public moments after the White House flag was returned to half-staff Monday afternoon following complaints from two of America's most prominent veterans' groups.

The White House flags had been lowered Sunday, the day after the Arizona Republican succumbed to brain cancer at the age of 81. However, they were back to full height on Monday, breaking with tradition.

In a statement directed to Trump, American Legion National Commander Denise Rohan wrote: "On the behalf of The American Legion's two million wartime veterans, I strongly urge you to make an appropriate presidential proclamation noting Senator McCain's death and legacy of service to our nation, and that our nation's flag be half-staffed through his interment."

VFW spokesman Joe Davis said in a statement the organization had "asked the White House if the honor of lowering the flag to half-staff could be extended through Senator McCain's interment."

Aides to Senate Majority Leader Mitch McConnell. R-Ky., and Minority Leader Chuck Schumer, D-N.Y., previously requested the Defense Department keep flags at government buildings lowered until the sunset after McCain is buried. McCain served in the chamber for six terms, most recently as chairman of the Armed Services Committee.

U.S. Flag Code states that flags be lowered "on the day of death and the following day for a Member of Congress."

McCain was a frequent critic of Trump on everything from his leadership style to his Russia policy. Trump questioned the decorated Navy pilot's Vietnam heroism and chafed at McCain's vote to stop the president's proposed "ObamaCare" repeal.

After Democratic Sen. Ted Kennedy of Massachusetts died in 2009, President Barack Obama ordered flags at the White House flown at half-staff for five days.

The Associated Press contributed to this report.

EDITOR’S NOTE: A previous version of this report stated that under “standard procedure,” the U.S. flag remains at half-staff until after a senator’s burial. U.S. Code states that the flag shall be flown at half-staff “on the day of death and the following day for a Member of Congress,” including U.S. senators.