It has been six days since massive floods struck the Himalayan mountainous region along the Nepal-China border.

Nepalese authorities are making all-out efforts to rescue an estimated 900 or so people believed to be trapped inside the tunnels of hydroelectric power plants.

On the 31st local time, the Nepal Disaster Management Authority stated that an estimated 933 workers are believed to be trapped inside the tunnels of about six hydroelectric power plant sites across Nepal due to the massive floods.

Accordingly, rescue operations are focusing on gaining access to the tunnels of these facilities, including the Trishuli 3A and 3B hydropower plants in Bagmati Province, central Nepal, which are among the affected areas.

Among them, at the Trishuli 3A plant, rescue workers successfully drilled four holes into the upper part of the tunnel the previous day and managed to enter the interior.

Rescue teams are currently working to check the locations and conditions of the people trapped inside.

Photos and videos shared by the rescue teams showed heavy machinery digging out and clearing mud and rocks, while rescue workers including the Nepalese army and police went into pits trying to find spaces to enter the tunnel.

Raja Ram Basnet, a spokesperson for the Nepalese army, told Reuters, "We are facing immense difficulty in opening the tunnels because of the massive amount of debris accumulated," adding, "Our primary objective is to open the tunnels."

Narendra Pariyar, the chief administrator of Rasuwa, the hardest-hit district, reported that rescue operations gained speed as the weather improved that day.

However, it remains unconfirmed whether the Upper Trishuli-1 power plant, where there is a possibility of missing South Korean nationals, is included among these six facilities.

Surendra Dhauluri (33), an Indian worker who had been working at the Upper Trishuli-1 power plant and was rescued on the 29th, told AFP that at the time of the flood, "I heard a very loud noise and saw the turbine room floor submerged in mud and ice-mixed water, trapping six workers inside."

He added that some workers managed to evacuate to high ground or construction zones beyond the reach of the flash floods, saying, "We rescued five of them, but one person died."

That day, the South Korean government joint rapid response team planned to move an overland search team consisting of nine personnel from the National Fire Agency to the Ramche area, located 1 to 2 kilometers away from the accident site, and have them camp there overnight.

They also plan to attempt searches using helicopters and unmanned aerial vehicles (drones) with the permission of Nepalese authorities.

According to the Nepal Disaster Management Authority, as of that day, the death toll from floods within Nepal has risen to at least 903, with 4,247 people reported missing, including 592 foreign nationals.

Combined with the 16 deaths and 546 missing persons (including 261 foreign nationals) in China's Xizang (Tibet) Autonomous Region tracked by Chinese authorities, the total casualties from these floods reach at least 919 dead and 4,793 missing.

Authorities in Uttar Pradesh, northern India, bordering Nepal, stated that they have recovered 17 bodies believed to be flood victims from locations such as the Gandak River, downstream from Nepal's flood-hit Trishuli River.

Indian authorities are verifying the identities of these bodies, and they have not yet been included in the official death toll released by Nepalese authorities.

Prime Minister Balen Shah of Nepal wrote on Facebook, "Our country is facing an unimaginable and heartbreaking natural disaster," adding, "It is extremely difficult to fully grasp the scale of damage to human lives, property, and infrastructure."

He further noted, "Although bad weather, rugged terrain, and ongoing risks bring difficulties to this mission, we will move forward with the determination to protect the lives of our citizens."