A plane operated by Nepal’s Tara Air carrying 22 people went missing on Sunday morning, an airline spokesperson confirmed to CNN.

The plane was flying from the city of Pokhara to Jomsom, a popular tourist town in central Nepal. The aircraft took off at 9:55 a.m. local time and lost contact with air control about 12 minutes into the flight, Nepal’s Civil Aviation Authority said.

Flights between the two cities are usually 20-25 minutes long. There were 19 passengers and three crew members on board, the spokesperson said.

Authorities believe the incident was caused by poor weather, according to Binod B.K., an official at the Nepal’s home ministry.

Two German nationals, four Indians and 13 Nepali citizens are among the 22 people missing, according to the ministry. The nationalities of two passengers are unknown.

The plane lost contact with the control tower five minutes before it was due to land at Jomsom, an airline official told Reuters on condition of anonymity. Tara Air mainly flies Canadian-built Twin Otter turboprop planes. Flight-tracking website Flightradar24 said the missing aircraft made its first flight in April 1979.

The spokesperson added that the Nepalese Army has been enlisted to help search for the missing plane.

Officials told Reuters that cloudy weather was preventing search helicopters from flying into the area of the flight’s last known location.

The country’s weather office said there had been thick cloud cover in the Pokhara-Jomson area since the morning. One search helicopter was forced to return to Jomsom due to the conditions.

“Helicopters are ready to take off for search from Kathmandu, Pokhara and Jomsom once weather conditions improve. Army and police search teams have left towards the site,” Nepal’s Civil Aviation Authority said in a statement.

Police official Prem Kumar Dani said a land-based search-and-rescue team had been sent to the area near Mount Dhaulagiri, the world’s seventh-highest peak at 26,795 feet (8,167 meters).

Nepal, home to eight of the world’s 14 highest mountains, including Everest, has a record of air accidents. Its weather can change suddenly and airstrips are typically sited in difficult-to-reach mountainous areas.

In 2016, a Tara Air flight crashed while flying the same route as the aircraft that was lost Sunday. That incident involved a recently acquired Twin Otter aircraft flying in clear conditions.

And, in early 2018, a US-Bangla Airlines flight from Dhaka to Kathmandu crashed on landing and caught fire, killing 51 of the 71 people on board.