Washington: US President Donald Trump plans to issue a proclamation Tuesday ordering flags flown at half-staff on federal buildings to honor the five victims of the Capital Gazette shooting in Annapolis, the White House said.

The decision follows a request by the Australian mayor of Annapolis, Democrat Gavin Buckley, which he said was initially denied.

White House spokeswoman Lindsay Walters said the decision was made on Monday night "as soon as the President heard about the request from the mayor".

She said that White House Press Secretary Sarah Huckabee Sanders spoke with Buckley both on Monday night and on Tuesday morning to alert him to the decision.

In an interview earlier Monday with The Capital newspaper, Buckley said he was disappointed to hear that his request would not be honoured.