Chinese coast guard personnel briefly boarded a Taiwanese tourist boat near Taiwan-controlled islands next to China’s coast on Monday, the government in Taipei said, in an escalation of tensions after China said it would carry out regular patrols.

China announced on Sunday that its coast guard would strengthen law enforcement activity around the Kinmen islands following the death of two Chinese nationals fleeing Taiwan’s coast guard having entered into prohibited waters too close to Kinmen, which lies opposite the Chinese cities of Xiamen and Quanzhou.