Taiwan says its planes warned off Chinese military aircraft that crossed the center line in the Taiwan Strait, calling China's move a provocation seeking to alter the status quo in the waterway dividing the island from mainland China.

Taiwan's defense ministry said a pair of Chinese J-11 jet fighters crossed the line around 11 a.m. Sunday and entered the island's southwestern airspace. It said Taiwan scrambled jets to warn off the Chinese planes, which came within about 185 kilometers (115 miles) of the island itself.

The ministry said in a tweet that the Chinese planes "violated the long-held tacit agreement by crossing the median line" of the strait.

Taiwanese President Tsai Ing-wen told reporters that such acts sought to alter the status quo and threatened regional security and stability.