A report of an active shooter on Friday inside an office building in downtown Washington was unfounded and began when a man pointed two toy guns that shoot cylindrical sponges out a window, D.C. police said.

Police issued an active-shooter warning on Twitter about 3 p.m. and told people to shelter in place in and around the building in the 1400 block of I Street NW, near Franklin Square. The alert was lifted about 3:40 p.m.

D.C. police said they searched the building, which includes a fast-food restaurant and a chiropractor clinic and is next to the McPherson Square Metro station. Police said they found no casualties or threats.

Police said they recovered the sponge guns and three-inch-long sponges called “bullet darts.” As least one of the toys was made by Nerf, which has several styles, including the Zombie Strike Doominator Blaster and the N-Strike Elite HyperFire Blaster. Police did not say which version of the toy had been used.

As of late Friday afternoon, police said they had not found the man who had the “guns.” Police said they did not know if the man was playing around or pretending to shoot people. It was also unclear whether any crime had occurred.

Clarence Williams and Ellie Silverman contributed to this report.