Chinese President Xi Jinping commissioned three main battle warships into the Chinese People's Liberation Army (PLA) Navy on Friday, the service's 72nd founding anniversary, according to Chinese state media.

According to report footage, the three warships are likely a Type 09IV nuclear-powered strategic ballistic missile submarine, a Type 055 large destroyer, and the country's first Type 075 amphibious assault ship, observers said, noting that the displacement of the three vessels combined is larger than the total displacement of many countries' entire navies, Global Times reported. Taiwan National Security Bureau (NSB) Director-General Chen Ming-tung said on Monday that he is aware of China's latest warships in Hainan, Taiwan News reported.

He remarked that it is clear Beijing's actions in the South China Sea have increased tensions with neighbouring nations, and the NSB is paying attention to all aspects of these developments. China claims sovereignty over almost the entire South China Sea and has overlapping territorial claims with Brunei, Malaysia, the Philippines, Vietnam and Taiwan.

China has been increasing its maritime activities in both the South China Sea and the East China Sea over the past few months, partly in response to Beijing's concerns over the increasing US military presence in the region because of escalating Sino-US tensions. Chen pointed out that it is evident China has stepped up its military buildup in recent years.

Tensions between China and Taiwan have escalated in recent times. Beijing claims full sovereignty over Taiwan, a democracy of almost 24 million people located off the southeastern coast of mainland China, despite the fact that the two sides have been governed separately for more than seven decades.

Since mid-September of last year, Beijing has stepped up its gray-zone tactics by regularly sending planes into Taiwan's ADIZ, with most instances occurring in the southwest corner of the zone and usually consisting of one to three slow-flying turboprop planes. Over the past few months, Taiwan has reported incursion by Chinese warplanes into ADIZ almost daily.

Last month, Taiwanese premier Su Tseng-chang termed the incursion by Chinese warplanes into Taiwan's Air Defense Identification Zone (ADZ) as "unnecessary" and "thoughtless".