KATHMANDU (AFP) - A British mountaineer's interview with the BBC on his smartphone from the top of Mount Everest has stirred controversy, with the Nepalese government calling the broadcast "illegal", officials said on Monday.

British mountaineer Daniel Hughes gave a "live" video interview to the BBC on his smartphone from the 8,848m peak on Sunday morning.

"This is the world's first live video call - never been done before - from the rooftop of the world," said the climber while breathing heavily through an oxygen mask and wearing a clown's red nose for charity.

"I don't have a cameraman with me. It's me with a pole, an HTC smartphone... and of course my red nose. It's a very proud moment to be here and 21/2 years in the making," he added.

The mountain has had mobile phone coverage for several years.

But Mr Purnachandra Bhattarai, joint secretary of Nepal's Tourism Ministry, told Agence France-Presse that Mr Hughes had broken the law by not seeking permission from the government for his broadcast.

"Even the tourism ministry has to seek permission from the communication ministry to film, broadcast or conduct media related events on Everest," Mr Bhattarai said.

He added that Mr Hughes' trekking agency was under investigation as a result of the incident, but did not elaborate further.

During a so-called "fair weather" window on Sunday, 146 people reached the summit of the world's highest peak, featuring teams claiming records for the first women from Saudi Arabia and Pakistan, Indian sisters as the first twins, and a British climber completing the feat for his eleventh time.

Mr Hughes was climbing to raise money for a British-based charity.

The mountain has become a popular symbolic pilgrimage site for record-setting, awareness-raising, and pledge drives for charities, which have increased crowds on the mountain.

Last year, more than 250 climbers reached the summit in a 48-hour stretch of good weather, despite warnings of potentially deadly bottlenecks in the "death zone" above 8,000m.

A brawl between European climbers and Nepalese Sherpas high on the mountain in April cast a shadow over the climbing season, which marks the 60th anniversary of Sir Edmund Hillary's and Sherpa Tenzing Norgay's maiden summit climb.

"This summit season has already been marked by controversy and we don't want it to happen again," said Mr Bhattarai.