From Dusk Till Dawn (1996)

The Gecko brothers, two dangerous outlaws on a wild crime spree, kidnap a father and his two kids and head south to a seedy Mexican bar to hide out in safety. Soon they realize that they're not in a typical bar, as the entire place begins to teem with vicious, blood-sucking vampires. With the odds stacked greatly against them, the Geckos are forced to team up with their hostages in order to make it out alive.