Taipei said on Wednesday that China's aircraft carrier had entered the Taiwan Strait, heightening tensions as the bitter divide between the two rivals approached the boiling point.

The Taiwanese government has urged its citizens to remain calm, and said both its own F-16 fighter jets and Japanese military surveillance were closely keeping tabs on the situation.

"The military is monitoring the whole situation and will act as necessary. We urge Taiwan's people to be at ease," read a statement from the Defense Ministry.

Chang Hsiao-yueh, Taiwan's minister of the Mainland Affairs Council, said Wednesday that 2017 would be a challenging year for ties with China.

"Any threats would not benefit cross-strait ties," he said.

Disputed territory

The Liaoning, China's only aircraft carrier, was dispatched to the South China Sea last month in a visit to territory disputed among several regional neighbors and which Beijing claims as its own.

As it made its return on Wednesday, it sailed along the line dividing the Taiwan Strait between what is considered its own territory and that belonging to Taipei. Some saw the move as a statement that China is willing to back up its territorial claims with military means, if necessary.

Ma Xiaoguang, a spokesman for China's Taiwan Affairs Office, told reporters on Wednesday that he had no information on the Liaoning's passage through the Taiwan Strait.

"Looking ahead in 2017, the development of cross-strait relations faces increased levels of uncertainty and the challenge of risk has risen," he said at a bi-weekly briefing.

Commissioned in 2012, the Liaoning was built from a repurposed Soviet hulk and has become a symbol of a new level of might and sophistication in the Chinese military machine.

Since splitting in 1949, Beijing and Taipei have maintained an uneasy truce. However, ties have rapidly deteriorated since the island's election of pro-independence President Tsai Ing-wen in May 2016. Mainland China has warned that the president risks further stoking tensions if she refuses to acknowledge Beijing's claim that Taiwan belongs to China.

es/cmk (AP, AFP)