The Undead (aka Mutant Vampire Zombies From The Hood) DVD

As the leaders of the rival neighbourhood gangs are making a deal in an isolated warehouse, the police are waiting to make a bust. The deal goes sour and, in an eruption of violence, one of the policemen is gunned down. The fighting is abruptly ended as a massive solar flare hits Earth and everyone in the warehouse collapses under the explosion. When they come to a few hours later, they soon discover that anyone directly exposed to the flare has joined the undead. It's a whole new world where zombies rule in this post apocalyptic world...the gangs need to work together to stand any chance of living but tensions are never far below the surface as they fight for their own survival.