More than 900 workers at different hydropower projects have been declared missing amid rescue operations after the destructive floods that swept through the Nepal-Tibet border on Wednesday.

Footage of the rescue efforts online showed the Nepali Army trying to save people trapped inside a hydropower tunnel in Rasuwa District on Sunday.

While 279 workers had been rescued, or managed to find their way out of the mud, countless others were still trapped, especially at the Trishuli 3A hydropower plant.

Local police said at least 788 people had died following the incident, while Chinese authorities had also reported at least 16 deaths. 

Reports noted that an estimated 3,000 people were missing across both countries, including foreign nationals. 

The U.S. Department of State said about 85 Americans were unaccounted for as of Sunday morning.

Meanwhile, Nepal authorities have commenced mass burials for unidentified victims of the unfortunate flood incident.