One person has died and another was taken to the hospital following a fire that broke out in a residence at a Pleasanton mobile home park late Wednesday night.

According to the Livermore-Pleasanton Fire Department, firefighters were called to the 3200 block of Vineyard Avenue shortly before midnight.

When crews arrived, firefighters found a mobile home in flames along with heavy smoke. Crews also heard reports of one person who was trapped inside.

As firefighters were working to put out the fire, a flashover occurred, forcing crews to retreat as the home became fully involved. Firefighters were eventually able to reenter the home and extinguish the flames.

One person inside the home was able to escape and was taken to a hospital by ambulance, firefighters said. A second person died at the scene.

Firefighters did not release the victim's identity.

In a statement Thursday, firefighters said the source of the fire is not known and that an investigation is underway.