China on Thursday condemned the U.S. military for the "illegal and provocative" flight of one of its aircraft over China's Taiwan, saying the move infringed upon China's sovereignty and contravened international law.

Foreign Ministry spokeswoman Hua Chunying said the U.S. move seriously violates international law and China firmly opposes and condemn such action.

"We urge the U.S. side to strictly abide by the one-China principle and the provisions of the three Sino-US joint communiques and to immediately stop such illegal and provocative acts," Hua told reporters after a daily briefing in Beijing.

A U.S. C-40 military transport aircraft was identified flying over the west coastline of Taiwan on Tuesday morning, Taiwan media reported, citing the island's defense authority.

The U.S. aircraft took off from Japan's Okinawa island, where there is a major U.S. air base, and flew over northern and western Taiwan on its way to Southeast Asia, Taiwan media reported.

Hua's remarks followed a similar statement earlier the day from the Taiwan Affairs Office of the State Council.

Zhu Fenglian, a spokesperson for the office, expressed strong dissatisfaction with and opposition to the U.S. move and noted that it damaged China's sovereignty and security, violated international law and the basic norms of international relations.

The Democratic Progressive Party (DPP) authority is ganging up with foreign forces to damage national sovereignty, security and peace across the Taiwan Straits, Zhu said, adding that the Chinese mainland has the determination, will and ability to safeguard the country's sovereignty, security and development interests.

Zhu warned the DPP administration not to misjudge the situation and underestimate Chinese people's firm will to safeguard national sovereignty, and urged it to stop such acts.