PORTLAND, Ore. (KOIN) — Authorities are investigating after a Molotov cocktail was found hidden near a downtown Portland building.

Portland police announced the discovery Thursday evening. A security guard for the building, which was not identified, found the Molotov cocktail during a routine check of the premise just before 1 p.m. and called police, according to authorities.

The Portland Metropolitan Explosive Disposal Unit came to the scene. Police did not release any more details.

The investigation is ongoing.

Police also said they’re looking into other similar incidents, but did not immediately elaborate if those incidents were connected to the ongoing protests, which have descended into unrest at times, including a declared riot last Friday that saw multiple fires lit through the streets of downtown. Dozens have been arrested and face charges in connection with the protests.

Anyone with information on these incidents is asked to contact Portland Police Bureau Detective Meredith Hopper at meredith.hopper@portlandoregon.gov or to call at 503.823.3408.