KATHMANDU, Nepal — Inexperienced climbers and overcrowding are being blamed for this season's high death toll on Mount Everest.

Photographs showing long lines on the world's highest peak have sparked debate over whether tougher government restrictions are needed to limit the number of people embarking on the dangerous trek.

At least 11 people, including three Americans, have died on Everest this month. Delays from overcrowding near its peak can put climbers at risk of altitude sickness, hypothermia and other complications.

A path on Mount Everest on May 22. Nirmal Purja / AP

However, a major factor contributing to this deadly season has been that about half of climbers embarking on the journey are inexperienced, one guide told NBC News.

"They don't train very hard. They underestimate Everest," said Jangbu Sherpa, who has been working on Everest since 2006. "There are lots of climbers who just want to check the box so that they can say they’ve been to the top of the world."

Some operators also fail to confirm the experience level of climbers and simply accept anyone who can afford the cost of the journey and ascent, he added.

Nepal is one of the world's poorest countries and takes in $300 million each year from climbing.

"The companies need to take responsibility for the climbers they are bringing here," said Ben Jones, an American who summited the mountain last week while working for Alpine Ascents International. "It's incredibly sad and I think most of the deaths are fairly preventable with good judgment, good decision-making."

Sherpa believes Nepal's government needs to impose and enforce tougher standards for those seeking climbing permits.

A record 381 permits were issued this year.

Gokul Prasad Baskota, Nepal's minister for communications, disputed that congestion on Everest was being caused by the system of allocating climbing permits. He pointed the finger at the climbers who hadn't completed enough training.

The Nepal Mountaineering Association, an umbrella body of expedition operators, said it would push the government to implement requirements for climbers to be adequately prepared.

"The government needs to come up with strict policies to control the inexperienced climbers from attempting to scale Everest," said Santa Bir Lama, the group's president.

Richard Engel and Chapman Bell reported from Kathmandu, and Linda Givetash from London.