Although Manipur and some other regions will be the first to vote in the seven-phase election starting on Friday, campaign meetings are being held behind closed doors because of a fear of violence
The Twin Otter aircraft, operated by private Tara Air, was on a flight from Pokhara, 125 km west of the capital, Kathmandu, to Jomsom when it lost contact with the control tower.
"It has broken into pieces," police officer Bishwaraj Khadka told Reuters from Myagdi, the town nearest the crash site. "There are no survivors." A Chinese national and a Kuwaiti citizen were among the dead.
Officials said thick fog had enveloped the Mustang area where Jomsom is located.
Mustang is a popular hiking area on the Mount Annapurna trekking circuit. A similar aircraft crashed in west Nepal in 2014, killing 18 people.