At least 49 people have been killed when an airplane belonging to Bangladeshi carrier US-Bangla crashed during its approach to a runway at Kathmandu international airport on Monday in what the airport and airline said was an accident due to a communications errors between aircraft and the Nepali air traffic control tower.

The Bombardier Dash 8 Q400 aircraft flying in from Dhaka had 71 people on board, including four crewmembers, when it skidded off the runway at the Tribhuvan International Airport in the Nepali capital at around 2.20 pm local time, prompting a huge emergency operation as first responders began to sift through the smoldering wreckage for survivors.

"We are not making any allegations," said US-Bangla CEO Imran Asif at a press conference in Dhaka. "We suspect that there might be negligence on Nepal's part, with the Kathmandu (air traffic control) tower giving misinformation to our pilots and this is why the accident took place," he added.

He said air traffic control gave the flight S2-AGU pilots conflicting information about which runways to land on.

"The negligence was not from our part, it was from ATC tower," he added.

However, Raj Kumar Chhetri, General Manager at Tribhuvan International Airport said the preliminary investigation showed the confusion had arisen in the cockpit of the aircraft.

Kumar Chhetri told reporters that air traffic control had requested the pilot land the aircraft from the south, something he said was described as "runway 20."

“Our preliminary findings show the captain said he was comfortable to land from runway 02, despite the air traffic controller telling him not to do so,” he said.

Earlier, Nepal's police spokesperson, Manoj Neupane, confirmed the death toll to EFE and added that 22 people were also injured in the crash whose cause remained unknown.

Neupane had added that all the bodies have been recovered from the plane.

US-Bangla said the airplane that crashed at Kathmandu was carrying 40 passengers from Bangladesh, 25 from Nepal, one from China and another from the Maldives, as well as four crew members, also from Bangladesh.

Some 65 of the passengers were adults and two were children, the spokesperson added.

This was one of the worst aircraft crashes in recent years in Nepal, which has witnessed several small aircraft crashes in the last decade that killed dozens, mostly tourists.