WASHINGTON — The Warner Theatre and adjacent buildings were evacuated, out of what D.C. police called “an abundance of caution,” as police investigated a suspicious package on Tuesday morning.

The investigation closed streets surrounding the theater including Pennsylvania Avenue, 13th Street and E Street. The resulting closures created gridlock throughout Downtown D.C. Entrances to the nearby Metro Center Station were also closed.

Police said they had ended their investigation about 11:30 a.m. and traffic conditions were beginning to ease. All Metro station entrances have reopened.

The first road closure was reported about 8:30 a.m., but more blocks were closed as the morning continued.

Traffic was backed up in the Third Street Tunnel and Constitution Avenue was jammed as drivers tried to work around the blocked roads. Traffic moved slowly on Fourteenth and F streets, which remained open.

On Monday morning, a suspicious package investigation at the FBI’s Hoover Building, which is several blocks from the Warner Theatre, also closed a several-block stretch of Pennsylvania Avenue.