Taiwanese officials have released rare satellite images of Chinese military bases which they say underscore the threat the island faces.
Twenty satellite images were released
The pictures appear to show Chinese fighter aircraft based across the Taiwan Strait, and evidence of practising for an attack on Taiwan.
Defence Minister Lee Jye said Taiwan had to strengthen its defences.
He appealed to politicians to approve a controversial bill to purchase billions of dollars worth of arms from the US.
"We are racing against time. If we don't do it today, we'll regret it tomorrow," he said.
The bill has been blocked in parliament more than 40 times by lawmakers who believe the purchase is too expensive and unnecessarily provocative.
Although Taiwan has had its own government since 1949, China regularly warns that it will use force against the island if it moved towards formal independence.
Taiwan's ally, the US, warned last year that China's was building up its capability to strike against the island, and had more than 700 missiles pointed in its direction.
At a press conference, Taiwanese officials showed reporters 20 satellite pictures of what they said were sites in China.
One of the pictures showed Russian-built Su-27 fighters said to be based in Fujian province, across the Taiwan Strait. Others were said to show evidence of Chinese war games simulating attacks on the island.
A military spokesman said photographs of Dahuo Island in China showed a staged attack on fighter jets of the type used by Taiwan.
"Posing the biggest threats to Taiwan are the ballistic missiles deployed in Leping, Yongan, and Ganzhou in Jiangxi province," an unidentified military officer told reporters.
Despite the government and military's backing for the arms purchase, some experts say Taiwan should boost its basic defences rather than spend billions of dollars on a package of relatively sophisticated arms, says the BBC's Caroline Gluck, in Taipei.