Taiwan's top military official is among eight people killed when a military helicopter made an emergency landing in mountainous terrain, officials say.
General Shen Yi-ming and 12 others were on the Black Hawk helicopter when it was forced to land in poor weather near the capital, Taipei.
Earlier reports said some people had been found alive, with others "trapped under fragments of the helicopter".
The general was flying to an army base in the north-east of Taiwan.
Several other top military officials were also on the helicopter, reports said.
Taiwan's air force sent two more Black Hawk helicopters and about 80 soldiers to the scene near Tonghou Creek in Wulai, the official Central News Agency reported.
The helicopter took off from Songshan air base in Taipei at 07:54 local time (23:54 GMT), bound for a military base at Dong'ao in Yilan county for an inspection, Focus Taiwan said.
It made the emergency landing after aviation authorities lost contact with it at 08:22, the defence ministry said.
A search and rescue team tried to get to the scene as quickly as possible but efforts were complicated by the terrain, an official told the BBC.
The US sold 60 UH-60M Black Hawk helicopters in 2010. It was not immediately clear whether the helicopter in Thursday's incident was one of them.
Taiwanese President Tsai Ing-wen, who hopes to be returned to power in elections on 11 January, cancelled campaigning on Thursday.
Ms Tsai from the Democratic Progressive party is running against Han Kuo-Yu of the Kuomintang party, which wants closer engagement with China.
Taiwan has been ruled separately since the end of the Chinese civil war in 1949.
But Beijing sees the island as a province to be reunified with China one day - by force if necessary.