China slammed the United States on Monday for "endangering" calm and stability in the Taiwan Strait after a P-8A Poseidon maritime patrol aircraft that was on a reconnaissance mission crossed through the waterway separating mainland China from the Taiwan island.

The Eastern Theatre Command of China's People's Liberation Army said that "the U.S. side's actions deliberately interfered with and disrupted the regional situation and endangered peace and stability in the Taiwan Strait. We firmly oppose this," adding that it has closely monitored the military plane.

"Theatre forces remain on high alert at all times and resolutely defend national sovereignty and territorial integrity," the statement added.

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A new Beijing white book, released in August 2022, said China reserves the right to take all necessary measures in response to the provocations by instigators of Taiwan’s separatism if a peaceful resolution to reunite with the island fails.

"To protect the interests of the Chinese nation as a whole, including our compatriots in Taiwan, we must resolutely oppose it and work for peaceful reunification," the book stressed, stressing, however, that failure to reach peaceful reunification with the island, including the "last resort" of the use of force.

Beijing has repeatedly urged the US to stop selling armaments to Taiwan and cut its military ties with the island. However, the US approved a potential $180 million arms sale to Taiwan in December amid ongoing tensions between the island and Beijing.

Furthermore, despite China's anger at a flurry of trips to Taiwan by US politicians in recent years, Taiwanese President Tsai Ing-wen said last Tuesday, after meeting with visiting US lawmakers, that Taiwan will boost military exchanges with the United States to curb alleged "authoritarian expansionism".

"Taiwan and the United States continue to bolster military exchanges," Tsai said after convening with the US delegation at her office in Taipei, adding that "going forward, Taiwan will cooperate even more actively with the United States" to confront "such global challenges as authoritarian expansionism."

Read more: The US does not desire conflict with China, 'so far': Biden

US-China relations have been strained due to provocative visits by US lawmakers, including House Speaker Nancy Pelosi, to Taiwan, despite objections from Beijing. 

Most recent provocations also include heightened tensions with Japan and allegations that China deliberately breached US airspace by sending alleged spy balloons to the US. 

Beijing has called on the US several times to cease spreading sentiments of sinophobia via its 'China threat' narrative and to break off the spell of a 'Cold War' mentality between the two global powers but to no avail.

Read more: US flying aircraft to South China Sea a muscle flex: Chinese diplomat

China accuses US of 'bullying' with new 'illegal' sanctions

In another context, China also accused the US of practicing “outright bullying and double standards” in leveling illegal sanctions on Chinese companies as part of US actions against Russia’s Wagner Group and related companies and individuals.

The entities were targeted for their alleged role in the war in Ukraine and "mercenary activities".

The sanctions “have no basis in international law or authorization from the Security Council, and are typical illegal unilateral sanctions and long-arm jurisdiction,” Foreign Ministry Spokesperson Mao Ning said at a daily briefing.

The punitive measures were “seriously harming China’s interests” and China “strongly rejects and deplores that and has lodged solemn complaints with the U.S. side,” Mao said.

“While the U.S. has intensified its efforts to send weapons to one of the parties to the conflict, resulting in an endless war, it has frequently spread false information about China’s supply of weapons to Russia, taking the opportunity to sanction Chinese companies for no reason," she said, slamming the move as "outright bullying and double standards."

The Treasury and State departments announced the moves in coordinated statements that targeted dozens of Wagner Group affiliates, including some in the Central African Republic and the United Arab Emirates, as well as the president of Russia’s Kalashnikov Concern, the original manufacturer of the AK-47 assault rifle.

The sanctions also hit the Chinese company Changsha Tianyi Space Science and Technology Research Institute Co. Ltd., also known as Spacety China. A Luxembourg-based subsidiary of Spacety China was also targeted.