Taipei: Former US Defence official Elbridge Colby stressed that an attack by China against Taiwan could happen with little warning as China has given up on "peaceful unification", reported Taiwan News.

Former US President Donald Trump's administration official Elbridge Colby has served as deputy assistant secretary of defence for strategy and force development in 2017-2018.

He has also been named as a possible candidate for a national security office if Donald Trump is elected president in the November presidential elections.

In an interview with Japan's Yomiuri Shimbun conducted in Washington DC, Colby said that the military needed to be strengthened so it could deliver any immediate response against Chinese aggression.

An attack could happen with little clear warning, he added, according to Taiwan News.

The former Pentagon official said that Chinese leader Xi Jinping had probably concluded that peaceful unification of Taiwan with China was not possible.

Colby said that a cross-strait war might involve the US, and US troops in the Asia Pacific, Japan, Australia, and the Philippines, as reported by Taiwan News.

Previous commentators, however, have said that China might find it difficult to launch a surprise attack against Taiwan, noting the range of preparations needed for such actions.

Colby advised the US to shift its support from Ukraine to Taiwan because Asia was now the "primary theater."

Additionally, he said that Washington should not abandon Europe, however, he sees Europe as much more able to handle Russia on its own than Asia would be facing China.

Earlier this month, China's Minister of National Defence Admiral Dong Jun warned "external forces" for emboldening Taiwan Independence separatists in an attempt to contain China with Taiwan and said that these malicious intentions are dragging Taiwan into a dangerous situation."

He said that anyone who dares to separate Taiwan from China will "end up in self-destruction."

Chinese Defence Minister said that some external forces keep "hollowing out" the one-China principle and continue to sell arms to Taiwan. He said that external forces were taking these actions to "Taiwan Independence separatists in an attempt to contain China with Taiwan" and stressed that these intentions are dragging Taiwan into a dangerous situation.

Days after Lai Ching-te was sworn in, China launched two-day-long military drills, surrounding Taiwan in what it called "punishment" for so-called "separatist acts," CNN reported.

The reason for China's drill is Lai's inaugural speech, in which he called on Beijing to stop intimidating the island nation, over which China continues to make its claim.

(With Inputs From International Agencies)