South China Sea Maritime Incident: Chinese Coast Guard Blocks Philippine Vessels
On January 24, 2025, Chinese Coast Guard intercepted Philippine vessels 3003 and 3004 attempting unauthorized entry near Tieline Reef in the South China Sea, demonstrating China’s increasing maritime law enforcement capabilities in the region.

The recent maritime incident between China and the Philippines highlights the ongoing territorial tensions in the South China Sea, particularly around critical maritime features like Tieline Reef. Located north of the Spratly Islands in China’s claimed waters, Tieline Reef consists of three coral reefs arranged in a northeast-southwest line, emerging during low tide. The eastern circular reef has a diameter of approximately 1,400 meters, while the middle elliptical ring reef lies about 3.5 nautical miles from Zhongye Island.
The strategic significance of this area extends beyond the immediate dispute. The South China Sea contains vast energy resources, with estimated oil reserves between 14-41 billion tons and natural gas reserves between 50-80 trillion cubic meters. This represents approximately 20% of China’s total oil and gas resources, making it a vital national interest.
China’s maritime enforcement capabilities have evolved significantly in recent years. The Coast Guard vessel involved in this incident was converted from a Type 056 missile corvette, demonstrating China’s enhanced maritime law enforcement fleet. This modernization reflects China’s strategy of maintaining presence and enforcing sovereignty claims through civil maritime forces rather than military assets.
The incident also reveals the complex regional dynamics at play. While the Philippines has occupied Zhongye Island (internationally known as Thitu Island) since 1971, China maintains effective control over various features in the South China Sea through a combination of civilian and military presence. The development of artificial islands and installation of facilities has strengthened China’s position in disputed areas.
This event occurs against the backdrop of broader geopolitical competition in Southeast Asia, where regional states must balance their relationships with both China and the United States. The Philippine response to such incidents is often influenced by domestic political considerations and its alliance commitments, particularly with the United States.
The maritime law enforcement action demonstrates China’s commitment to protecting its claimed maritime rights while avoiding military escalation. This approach of using coast guard vessels rather than naval assets represents a calculated strategy to assert sovereignty claims while managing the risk of conflict.