CHONGQING, China, June 1 (UPI) -- A passenger ship carrying more than 450 people flipped over on China's lengthiest river during a strong storm Monday night, Beijing's official news agency reported.
The vessel, the Eastern Star, was traveling along the Yangtze River from the eastern city of Nanjing to the southwest city of Chongqing when it abruptly turned over around 9:30 p.m. local time, China's state-run Xinhua News Agency reported.
The total number of passengers on the boat wasn't immediately clear, but reports indicate there were at least 457 -- including 405 passengers, five travel agency representatives and 47 crew members.
Initially, nine people were rescued from the water -- including the boat's captain and chief engineer. As of Tuesday morning, most of the others remained unaccounted for.
CCTV reported that all of the passengers were Chinese, and nearly a dozen rescue ships are aiding in the rescue effort.
The unnamed captain reportedly told investigators the vessel capsized quickly after becoming enveloped in a strong storm of rain and strong winds. Xinhua called the storm a "cyclone," and said the severe conditions in the area also made it difficult for rescuers to conduct a search for additional survivors or victims.
The part of the Yangtze River where the boat overturned is about 50 feet deep, officials said, but the bottom of the ship could be seen still floating above the water's surface.
Chinese Premier Li Keqiang traveled to Central China to direct the rescue efforts, Xinhua said, and President Xi Jinping dispatched other top officials to the scene.
The Eastern Star, which was built in 1994, can carry as many as 534 passengers and crew -- meaning the vessel was at 85 percent of capacity.
At nearly 4,000 miles, the Yangtze River is the third-longest in the world.