Kathmandu, Nepal (CNN) -- The search for an aircraft carrying 18 people, which has been missing in the mountains of western Nepal since Sunday afternoon, continued Monday morning, authorities said.
The 40-year-old Canadian-made Twin Otter aircraft in question belongs to state-owned Nepal Airlines.
It was flying from the tourist town of Pokhara, about 200 kilometers (124 miles) west of Kathmandu, en route to Jumla, a remote town about 600 kilometers (373 miels) northeast of Kathmandu.
"It was supposed to land at 1:45 p.m., but it did not arrive," said Bimlesh Karna at the rescue coordination center at Tribhuvan International Airport.
The flight usually takes an hour.
The plane was flying in inclement weather as it had been raining and snowing across the country for the past few days.
Among the 18 on board are three crew members and a Danish national. Of the 17 Nepalese, one is a child, Karna said.
Mingma Lama, senior superintendent of police, is heading a 150-member police search team. He said locals have reported that pieces of the aircraft have been found.
Bam Bahadur Bhandari, regional police chief in Pokhara, also said locals had seen wreckage. He said a search helicopter had also spotted the wreckage but could not find a place to land.
The disappearance of the plane has again raised concern over Nepal's air safety record. There were two fatal air crashes each year from 2010 to 2012 in this Himalayan country.