China is ramping up its presence east of Taiwan in an apparent bid to establish jurisdiction in the waters and counter Japanese-Philippine cooperation in the area — a move that could aid in a blockade or quarantine of the island, according to a new study.

The moves, which follow a May announcement by Tokyo and Manila launching maritime boundary talks for the area, include a “series of unprecedented operations” in the Philippine Sea by Chinese survey and law enforcement ships, the Center for Strategic and International Studies’ Asia Maritime Transparency Initiative said in .

The operations include the questioning of nearly 200 commercial vessels transiting the area, with Chinese ships demanding their ports of call and crew details, while also deploying a sustained law-enforcement presence, according to the report.