"On September 17, a US P-8A anti-submarine patrol aircraft flew through the Taiwan Strait," Li Xi, a senior captain and spokesperson for the Eastern Theater Command of the Chinese People's Liberation Army (PLA), said in a statement.

The PLA theatre command "organised fighter jets to tail and stand guard against the US aircraft's flight, dealing with it in accordance with the law", Li said.

"Theater troops are on constant high alert to resolutely defend national sovereignty and security and regional peace and stability."

Beijing views self-ruled Taiwan as a renegade province and claims jurisdiction over the body of water that separates the island from the Chinese mainland.

The US Navy's Seventh Fleet said in a statement that a "P-8A Poseidon transited the Taiwan Strait in international airspace on Sept. 17 (local time)".

The statement did not mention the aircraft being tailed by the Chinese military.

"By operating within the Taiwan Strait in accordance with international law, the United States upholds the navigational rights and freedoms of all nations," it said.

"The aircraft's transit of the Taiwan Strait demonstrates the United States' commitment to a free and open Indo-Pacific."

Taiwan's defence ministry said in a statement "a US P-8A aircraft passed through Taiwan Strait from south to north this morning".

"The military has monitored the situation and no anomaly was detected in our surroundings," it said.

China also accused Germany of heightening security risks in the Taiwan Strait on Saturday after two of its military vessels sailed through the waterway.

Taipei thanked Washington on Tuesday for approving $228 million worth of "return, repair, and reshipment of spare parts" for its aircraft and related equipment, the 16th such sale of arms to the island under US President Joe Biden.

Taiwan's defence ministry said in a separate statement the deal was expected to take effect in a month and "will help maintain the combat readiness and safety of various types of aircraft equipment of our air force".