Beijing, China – Taiwan's independence would mean war, China's military said on Thursday as it adopted a tougher tone in its dealings with Taiwan.

"Taiwan's independence means war," Chinese Defense Ministry spokesperson Wu Qian told the press in Beijing.

Taiwan is an inseparable part of China, he said, and defended recent Chinese air force operations that increasingly violate Taiwanese airspace.

The military activities are "necessary to deal with the current security situation in the Taiwan Strait and safeguard national sovereignty," the spokesman said.

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He called the flights a "serious response to foreign interference and provocations by Taiwan's independence forces," he added.

The People's Liberation Army will take "all necessary measures" to vigorously put down any "separatist conspiracy," he said.

The spokesperson addressed the US, which is committed to supporting Taiwan's defense capabilities, saying relations were at a "new historic starting point" now that President Joe Biden has taken office.

China hopes Washington will work with Beijing and avoid confrontation, he said, adding that containing China was an "impossible project."

After the increased number of incursions into Taiwan's airspace, the US State Department called on China to stop pressuring Taiwan.

Last year, violations of Taiwan's air defense identification zone had already reached their highest level since the 1996 crisis, but were stepped up again after Biden's inauguration.

Beijing views Taiwan as a breakaway province that will one day be reunited with China, though the now democratic island has had its own government since 1949.