(The Hill) — Taiwan’s defense ministry on Thursday said nine Chinese aircraft had entered its air defense identification zone, just hours after Russia had launched an invasion into Ukraine.

The ministry said that the mission involved eight J-16 sorties and one Y-8 reconnaissance aircraft.

The ministry also released the flight paths of the aircraft and said they flew over an area to the northeast of the Taiwan-controlled Pratas Islands, Reuters reported.

In response, Taiwanese fighters were deployed to warn the Chinese aircraft and air defense missiles were scrambled to “monitor the activities,” the ministry said, according to the news wire.

This comes just a day after China’s foreign ministry on Wednesday said Taiwan is “not Ukraine” and has always been a part of China amid Taiwanese President Tsai Ing-wen’s call for increased vigilance of military activities in response to the crisis in Ukraine. 

Chinese foreign ministry spokesperson Hua Chunying dismissed the concerns of British Prime Minister Boris Johnson, who said there might be worldwide consequences, including for Taiwan, if Western nations failed to support Ukraine’s independence, according to Reuters.

“Taiwan is not Ukraine,” Hua said while speaking in Beijing. “Taiwan has always been an inalienable part of China. This is an indisputable legal and historical fact.”

Tsai told her working group on the Russia-Ukraine crisis established by her National Security Council that all security and military units “must raise their surveillance and early warning of military developments around the Taiwan Strait,” Reuters reported.

In December, a U.S. defense official said there was an “urgent” need to enhance defenses in Taiwan as the threat of China annexing the country was “real and dangerous.”

“Bolstering Taiwan’s defenses is an urgent task,” said Ely Ratner, the assistant secretary of defense for Indo-Pacific security affairs. “We are modernizing our capabilities, updating U.S. force posture and developing new operational concepts.”