Taiwan’s defense ministry said on Saturday that it had tracked a new wave of Chinese military activity near the island, underscoring the persistent pressure Taipei faces in the Taiwan Strait. The ministry said it detected 18 Chinese aircraft and 10 naval vessels operating around Taiwan by 6 p.m. local time.

The reported movements add to a pattern of recurring military drills and patrols that have kept tensions high between Beijing and Taipei. Taiwan has repeatedly warned that such actions increase the risk of miscalculation and threaten regional stability.

Beijing claims Taiwan as its territory and has stepped up military and political pressure on the self-governed island in recent years. Taiwan’s government rejects China’s sovereignty claims and says only the island’s people can decide their future.

The latest detection comes amid continuing concern among regional and global policymakers about the security balance in the Taiwan Strait, a major shipping lane and flashpoint in U.S.-China relations.