A man with an artificial leg reached the summit of Mount Everest on Tuesday with a colleague who had conquered the peak just seven days earlier.

Nepal's tourism ministry said Tom Whittaker, a 49-year-old British-born American who is an outdoor pursuits instructor living in Prescott, Ariz., reached the highest point on Earth, 29,028 feet above sea level, at 7 a.m.Whittaker lost his right kneecap and foot in a car accident and wears an artificial leg fitted below the knee.

He told Reuters in March that he was determined to be the first disabled person to climb Everest and show what the disabled can accomplish.

He said that it takes him 30-35 percent more energy to climb mountains than able-bodied people.

Whittaker scaled Everest by the standard Nepalese route via the southeast ridge Tuesday night. He had left his highest camp, at 26,000 feet, at 11 p.m.

Whittaker reached the top with four Nepalese sherpas - Lhakpa Tsherinng, Da Sonam, Tashi Tshering and Norbu - and another American, Jeffrey Rhoads, who had already accomplished the feat on May 20 but decided to do it again with his disabled friend.

Rhoads, 43, is a photographer and mountain guide from Pocatello, Idaho.

On May 20, Whittaker climbed 27,000 feet before having to turn back because of a pulmonary infection.