President Obama has ordered that flags be flown at half-staff in honor of former Sen. Arlen Specter (Pa.), who died over the weekend.

Obama issued the presidential proclamation on Monday as "a mark of respect for the memory of Arlen Specter."

Flags will be flown at half-mast on Tuesday at the White House, military buildings and public grounds in the District of Columbia as well as United States embassies and consular offices.