The joint navy and air force combat readiness exercise was a “stern warning” to those colluding with foreign forces, the People’s Liberation Army said Saturday. In a later statement the PLA said it was testing the coordination and resistance capabilities of the Eastern Theater Command troops in the north of Taiwan with “submarine detection,” “anti-submarine” and other exercises.

Taiwan’s Ministry of Foreign Affairs and the Presidential Office both condemned China’s actions, saying they constituted serious provocation and urging it to end the exercises. Lin Yu-chan, spokesperson for the office, said China shouldn’t use Taiwan leaders’ trips as an excuse for the drills because there had been precedents in the past for these types of visits and transit stopovers.

China “has made it clear it wants to shape Taiwan’s coming national election,” Taiwan’s Minister for Foreign Affairs Joseph Wu posted on X, the social media platform formerly known as Twitter. “Look, China should hold its own elections; I’m sure its people would be thrilled.”

Earlier, Taiwan’s Ministry of National Defense said it’s closely monitoring the situation and has deployed aircraft, naval vessels and land-based missile systems in response.

Tensions rose last week after Vice President Lai Ching-te, 63, stopped over in New York and San Francisco en route to and from Paraguay for a state visit to one of the few countries that still has official diplomatic ties with Taiwan. China’s Taiwan Affairs Office said on Saturday that it strongly condemned Lai and accused his Democratic Progressive Party of colluding with the US.

Taiwan’s defense agency called China’s military exercises “irrational and provocative behavior,” and said 42 PLA aircraft were detected — 26 of which crossed the strait median line — since 9 a.m. Saturday. Eight Chinese naval vessels also took part in the patrols, it said.

China has used similar rhetoric about war with Taiwan in the past, including after President Tsai Ing-wen’s stops in the US in the spring. Those travels included a visit to Los Angeles, where she met House Speaker Kevin McCarthy and other US officials and lawmakers. Beijing has also previously referred to figures in the Democratic Progressive Party — to which Tsai and Lai belong — as troublemakers.

Bloomberg News published an interview with Lai on Tuesday, in which the frontrunner to be Taiwan’s next leader talked about relations with China and with the US. Beijing slammed Lai as a “troublemaker,” whose views risk sparking a conflict.

Lai used the Bloomberg News interview to spread “Taiwan independence” rhetoric, China’s Taiwan Affairs Office said in the Saturday statement.

The heated back-and-forth signals the cross-strait relationship is set for more challenges if Lai becomes Taiwan’s next president. He has been leading polls for months and has indicated that if he wins, he’ll continue policies that Tsai has pursued since starting the first of her two terms in 2016.

— With assistance by Jacob Gu and Cindy Wang