Taiwan’s defence ministry said on Friday that over the previous 24-hour period it had detected 24 Chinese air force aircraft entering into Taiwan’s air defence zone, part of a regular pattern of what Taipei calls Chinese harassment.

At least 17 of the aircraft crossed the median line of the Taiwan Strait, according to a map the ministry published.

The median line previously served as an unofficial barrier between the two sides until China’s air force began regularly crossing it last year. (Reporting by Ben Blanchard; Editing by Tom Hogue)