The black box of a crashed Nepali passenger plane was found on Monday, an official said.

"The security forces have found the black box a while ago. We will get it soon," Jagannath Niroula, spokesperson of the Civil Aviation Authority of Nepal (CAAN), told Xinhua.

Earlier in the day, the rescuers resumed the search for four people still unaccounted for after a passenger plane crashed on Sunday near Pokhara, a popular tourist destination in central Nepal.

Divers have been mobilized for search in the Seti River, as some dead bodies are feared to have fallen in it, Niroula told Xinhua earlier.

The Yeti Airlines plane carrying 68 passengers and four crew members went down in the Seti River gorge when it was flying from Kathmandu to Pokhara, and 68 bodies were recovered from the crash site on Sunday.

According to a CAAN statement, there were 15 foreigners aboard the ill-fated flight.

The Nepali government has declared a national holiday to mourn the dead on Monday and decided to form a five-member committee to probe into the cause of the accident, which is described as among the worst in Nepal's history in the past three decades.