A 13-year-old American boy has become the youngest climber to reach the top of Mount Everest, surpassing the previous record set by a 16-year-old Nepalese climber.

Jordan Romero's mother, Leigh Anne Drake, said her son had called her by satellite phone from the summit of the world's highest mountain, 29-thousand and 35 feet (8,850 metres) above sea level.

The teenager, from Big Bear, California, is now one climb away from his quest to conquer the highest peaks on all seven continents.

He climbed Mount Kilimanjaro in Africa when he was nine years old, saying he was inspired by a painting in his school hallway of the seven continents' highest summits.

But Everest was the young mountaineer's first challenge above 26,240 feet (eight-thousand metres).