A three-year-old Texas boy has died after shooting himself with a gun he found during his own birthday party, police said Monday.

The youngster was celebrating with family and friends on Saturday in Porter, 25 miles (40 kilometers) northeast of Houston, when adults heard a gunshot while playing cards.

The boy was found with a gunshot wound to his chest and rushed to a fire station where he died, the Montgomery County Sheriff's Department said.

Authorities said the boy had found a pistol that had fallen out of a relative's pocket.

The group Everytown for Gun Safety said that, since the beginning of the year, the country has seen at least 229 unintentional shootings by children, resulting in 97 deaths.

A third of US adults own a gun, with the right to own firearms guaranteed by the Second Amendment to the US Constitution.

Texas is among states with the most permissive gun laws.