Taiwan on Thursday detected at least 84 Chinese warplanes and 33 warships near its territory, as the People’s Liberation Army (PLA) conducted one of its biggest joint sea and air drills in months in the Western Pacific.

The drill involved 68 PLA aircraft and 10 PLAN vessels around Taiwan, according to the Taipei defense ministry. Some of the planes and warships were heading to an unspecified location in the Western Pacific to conduct joint sea and air training with the Shandong aircraft carrier.

The Shandong is China’s first domestically built aircraft carrier and its second battle group. It was spotted 60 nautical miles off Taiwan’s southernmost tip on Monday when it headed for combat training.

Twenty-eight of the Chinese planes crossed the median line and entered Taiwan’s southwest Air Defense Identification Zone (ADIZ). The ADIZ is a de facto line that separates the island from the mainland in the Taiwan Strait.

China has not officially commented on the drills, but its Eastern Theatre Command, which organizes drills around Taiwan, said on Wednesday that an aviation unit had carried out training recently in a range of thousands of kilometers.

The presence of the Shandong aircraft carrier has rattled Taiwan. Major General Huang Wen-chi, of the ministry’s general staff for intelligence, said that the Shandong would form a new risk for the island.

“The Shandong, flanked by such new destroyers as [the] Type 052C and Type O52D, evidently would form a considerable threat to our near-sea and coastal defence but the carrier still does not possess the full capability in air and sea strikes,” he said in Taipei on Tuesday.

The Chinese military drills come at a time of heightened tensions between China and the United States over Taiwan. The US has recently increased its military support for Taiwan, and Chinese President Xi Jinping has warned that China will not hesitate to use force to prevent Taiwan from declaring independence.

The situation in the Taiwan Strait is a major concern for the international community, as any conflict between China and Taiwan could have devastating consequences for the region and the world.