Pakistan, Sept. 21 -- United States President Donald Trump said on Sunday that the triumphal arch he plans to build near Arlington National Cemetery in Washington would double as a "military complex" housing drones and snipers, as well as storing large quantities of ammunition.

The president cited national security concerns for the move, echoing the rationale offered for the roughly $400 million ballroom complex being built on the site of the White House's former East Wing, which was demolished to make way for the project. He did not identify any specific threats.

The projects are part of Trump's ambitious effort to reshape Washington, including a push to add his name to the John F. Kennedy Centre for the Performing Arts. The plans have...