The Chinese People’s Liberation Army (PLA) Navy held live-fire anti-sea mine exercises involving warships and minesweeping robots to thwart Taiwan’s alleged attempt to surround Taiwan Strait with mines.

Chinese experts said the recent PLA drills displayed its ability to destroy mines laid by Taiwan to buy time for U.S. reinforcements. It also showed the PLA can break Taiwan’s sea mines ring to open passages for other warships and landing forces to enter into the island nation, Global Times reported Monday.

It is not known where the anti-sea mine drills actually took place. “Smart” mines that explode after sensing sound or magnetic field changes were hidden under calm seas. Sonar systems and minesweeping robots were deployed to detect, identify and dismantle the mines.

In this exercise, we comprehensively tested the anti-sea mine ships’ ability to react quickly, deal with complicated situations, and carry out anti-sea mine tasks by setting realistic combat scenarios, battlefield environment and difficult training subjects,” He Jing, captain of the Liuyang, told CCTV.

In addition to clearing different types of sea mines, including drifting and moored mines, the ships also conducted live-fire anti-aircraft exercises.