The Chinese government on Friday extended condolences to families of the victims of the train accident in Taiwan, which took place earlier in the day.
Ma Xiaoguang, a spokesman for the Taiwan Affairs Office of China's State Council, said that the mainland has been monitoring the rescue operation "with a strong concern," Kyodo News reported.
Japanese Prime Minister Yoshihide Suga offered his condolences following a deadly train accident on Friday in Taiwan that resulted in dozens of casualties.
"I am extremely heartbroken," Suga wrote on Twitter, which also appeared in Chinese. "I express my heartfelt sympathies to those who have died and offer my sincere condolences for the people who suffered in the accident."
"If there is a request from the Taiwan side regarding support, we want to consider possible assistance," Chief Cabinet Secretary Katsunobu Kato, Japan's top government spokesman, told a press conference.
The express train that derailed in a tunnel in eastern Taiwan was manufactured by Hitachi Ltd. and started operations in May 2007 as Taiwan's first tilting rail car, the major Japanese conglomerate said.
Under its push for infrastructure exports, Hitachi has delivered 260 rail cars, including those for express and bullet services, to Taiwan since 1960, including 64 tilting cars since 2006.
AFP reported that at least 51 people were killed in Taiwan on Friday when a packed train collided with a vehicle on the tracks and then derailed inside a tunnel, in the island's worst railway accident in decades.
Officials said the devastating collision was caused by a railway maintenance vehicle which slipped down an embankment above the tracks near the eastern coastal city of Hualien.
"(The driver) was suspected of not pulling the parking brake tight enough so the vehicle slid 20 meters... onto the train line," Feng Hui-sheng, deputy director of Taiwan Railways Authority, told reporters.
Local media images from the scene showed the back of a yellow flatbed truck on its side next to the train just a few metres from the tunnel entrance.
The eight-carriage train was packed with some 480 people heading down the east coast for the annual Tomb Sweeping Festival, a four-day public holiday.
The Taiwan Railways Agency said 146 passengers were sent to hospital in addition to the 51 confirmed dead.
A French national was among those killed while two Japanese and one Macau resident were injured.
One unnamed female survivor told TVBS news channel of trapped passengers -- some crying out for help, others unconscious.
"There were many people pressed under the seats and others on top of those seats too," she said.
President Tsai Ing-wen visited an emergency response centre in the capital Taipei, and said investigators would get to the bottom of how such a deadly crash could have occurred.