Beijing, Dec 28 (IANS): China on Wednesday said the Taiwan issue was a domestic affair of the country and the US should carefully handle it by abiding by the 'one-China policy'.

An Fengshan, spokesman for the State Council's Taiwan Affairs Office, said the Taiwan issue was a matter concerning national sovereignty and territorial integrity of China, Xinhua news agency reported.

It is also the "most sensitive and complicated issue in China-US relations", An said.

He was asked to comment on the US's 2017 National Defence Authorisation Act which includes the provision on military cooperation with Taiwan.

"We hope the US will abide by the 'one-China policy' and the three China-US joint communiques, and carefully handle issues related to Taiwan," the spokesman said.

China firmly opposes official and military relations between the US and Taiwan in any form, he said.

An reaffirmed China's clear and consistent opposition to arms sales by the US to Taiwan.

In response to another question, An said that a Chinese navy formation, including the aircraft carrier Liaoning, headed toward the West Pacific on December 24 for scheduled blue water training, which was carried out in accordance with the annual plan made by the navy.