The younger Mr Gore was freed on bail

Al Gore III, 24, was stopped by police as he sped at 100mph (160km/h) in his low-emission hybrid car in California.

Marijuana and prescription drugs were found during the search of the car. Mr Gore did not have prescription for any of the drugs, police said.

He was later released on $20,000 (£10,000) bail.

"We're glad that he's safe and that he's getting treatment," the former US vice-president told NBC News.

Mr Gore is one of the organisers of Live Earth

"We're going to leave it as a family matter," he added.

The younger Mr Gore was stopped after Orange County sheriff's deputies spotted his Toyota Prius speeding on a motorway near Los Angeles.

In 2003, Mr Gore was arrested for marijuana possession in Maryland, and in 2002 for suspected drink-driving in Virginia.

His latest arrest came just days before his father is due to take part in Live Earth - a worldwide series of concerts to raise awareness of climate change.