KATHMANDU - Around 15 workers, of whom 12 feared to be Chinese, have been trapped inside a tunnel of a hydropower project in west Nepal, police said.

The workers of the 25 MW Upper Madi Hydropower Project, which is under construction at Sildujure of Kaski district, some 250 km away from the capital Kathmandu, were trapped in the tunnel after a mudslide at an entrance of the tunnel at around 1:30 p.m. local time.

"As there were many Chinese nationals working inside the tunnel, we fear around a dozen of them have been trapped," Rajaram Koirala, the project coordinator of Upper Madi, told Xinhua.

He also said a rescue team from Nepal Police and Nepal Army has managed to open a passageway for the air to go through the tunnel.

"The rescue operation has already begun with necessary equipment being taken to the site," Bashanta Lama, chief of Kaski District Police Office, said.

Of the people trapped inside the tunnel, 12 were confirmed to be safe for the moment, said the police.

"During a communication through the use of plastic pipe, the workers trapped inside said 12 of them are safe while the condition of others is unknown," Ganesh KC, a police personnel who is in the rescue mission at the project site, told Xinhua over phone. "As demanded by the workers, we have also sent them water and air through pipe."

He said even the 12 trapped workers with whom the rescuers communicated are not sure about the actual number of workers trapped inside.

Rescuers said it will still take some two hours to rescue the trapped workers. Nepal Army, Nepal Police and locals have been making efforts to free the trapped workers.

More than 80 percent of the financial support to the project is from the China Three Gorges Corporation, while Sinohydro Bureau 10 of China is the contractor of the project.