Firefighters battled a large blaze Monday night at a commercial building on the 100 block of Broadway in Somerville, drawing crews from several other communities to assist, fire officials said. The building appears to house Rei da Picanha, a Brazilian restaurant, and a Santander bank branch. Other departments responded to the scene, while additional communities provided mutual aid to Somerville. Officials had not released further information immediately, including whether anyone was injured or the extent of damage. The cause of the fire was not reported.