A molotov cocktail was discovered this afternoon in a garage near a Center City office of the Department of Homeland Security and triggered an investigation by city police and federal authorities.

A bottle filled with diesel fuel was found just before 2 p.m. in the garage on the corner of Callowhill and North 16th Street. The garage is across the street from the Immigration and Customs Enforcement offices.

Initial reports said a laptop computer and several anti-Israel books were found with the device, which had been placed near a generator.

A tipster called police after seeing a man with several full trash bags emerge from a garage storage closet. A bomb squad unit "rendered safe" the molotov cocktail, said police spokesman Lt. Frank Vanore.

Police were trying to identify the man seen with the bags and determine if he was linked to the explosive device.

Contact staff writer Sam Wood at 215-854-2796 or samwood@phillynews.com.