Medics responded Monday afternoon and rescued a baby locked in a truck in Otay Mesa.
San Diego police received a report at 12:40 p.m. about a two-year-old locked in a truck outside a McDonald's in the area of Siempre Viva Road and Roll Drive.
Border patrol agents responded and shattered a window to free the baby, though it took 30 minutes to remove him.
The boy was checked out by paramedics and is doing OK. His mother did not speak English and declined to be interviewed by NBC 7.
The circumstances surrounding the baby being locked in the car were not immediately clear.
Witnesses said they didn't know why the baby was left in the hot truck. They said the mom had tried for 20 minutes to free him unsuccessfully.