Rival ships circle in high seas "cat and mouse" as Beijing is set to end its unprecedented four days of military exercises that could lower tensions in the region.

Chinese soldier watches Taiwan's frigate Lan Yang unprecedented Chinese military exercises.
Chinese soldier watches Taiwan's frigate Lan Yang unprecedented Chinese military exercises. (AP)

Chinese and Taiwanese warships have played high-seas "cat and mouse", hours before the scheduled end of four days of unprecedented Chinese military exercises launched in reaction to a visit to Taiwan by the US house speaker.

Some 10 warships each from China and Taiwan sailed at close quarters in the Taiwan Strait on Sunday morning, with some Chinese vessels crossing the median line, an unofficial buffer separating the two sides, according to a person with knowledge of the matter.

As Chinese forces "pressed" the line, as they did on Saturday, the Taiwan side stayed close to monitor and, where possible, deny the Chinese the ability to cross.

"The two sides are showing restraint, the person said, describing the manoeuvres as high seas "cat and mouse".

"One side tries to cross, and the other stands in the way and forces them to a more disadvantaged position and eventually return to the other side."

Taiwan said its shore-based anti-ship missiles and its Patriot surface -to-air-missiles were on stand-by.

Taiwan's Premier Su Tseng-chang said that China had "arrogantly" used military actions to disrupt regional peace and stability.

Speaking to reporters in Taipei on Sunday, Su also called on Beijing to not flex its military muscles, and condemned "foreign enemies" he said were attempting to sap the morale of the Taiwanese people through cyberattacks and disinformation campaigns.

Pelosi's visit triggers crisis

The Chinese exercises, centred on six locations around the island, began on Thursday and are scheduled to last until midday on Sunday. 

China's military said on Saturday it was conducting sea and air joint exercises north, southwest and east of Taiwan with a focus on testing land-strike and sea-assault capabilities.

Nancy Pelosi's visit last week to the self-ruled island infuriated China, which responded with test launches of ballistic missiles over the island's capital for the first time and the cutting of communication links with the United States.

The United States called the exercises an escalation.

China halted communication through various channels with the United States as part of its response to Pelosi's visit, including between military theatre commands and on climate change.

Taiwan has been self-ruled since 1949, when Mao Zedong's communists took power in Beijing after defeating Chiang Kai-shek's Kuomintang nationalists in a civil war, prompting their retreat to the island.

China says Taiwan is its province and its relations with the island are an internal matter and it reserves the right to bring the it under its control, by force if necessary. 

Source: TRTWorld and agencies