The United States currently has four massive marine national monuments in the Pacific Ocean that China has its eye on. Beijing’s interest in the more than 1 million square miles of ocean has raised national security concerns, according to Forbes.

The National Oceanic and Atmospheric Administration and the U.S. Fish and Wildlife Service maintain approximately 1.2 million square miles of marine national monuments between Hawaii and the Marianas Trench. The four monuments are the Papahānaumokuākea Marine Monument, the Marianas Trench Monument, the Pacific Remote Islands Monument, and Rose Atoll Marine Monument.

NOAA says the areas were designated by Congress to “protect the respective areas’ abundant and diverse coral, fish, and seabird populations; facilitate exploration and scientific research; and promote public education regarding the value of these national treasures.” It adds that they offer the “opportunity to protect areas of outstanding resource biodiversity and scientific, cultural, and aesthetic value, and provide for the long-term persistence of these natural and cultural legacies.”

These monuments are valuable to the U.S. for far more than just preservation. They’re also militarily strategic locations that have served as testing grounds for U.S. naval resources and training areas for defense assets. The monuments are also handy hiding places for American missile subs, Forbes noted. And as China looks to assert power in the region, the Pacific monuments become more tempting.

However, there’s a current lack of enforcement resources for the area. The U.S. Fish and Wildlife Service has zero large vessels to patrol the monuments, so the government has relied on the overstretched Coast Guard for enforcement. This lack of resources has led analysts to see the monuments as a prime target for Beijing.

The Forbes report suggested that it’s time the U.S. Department of Interior get involved and get invested in “enforcing U.S. law and American sovereignty” at the monuments.

“America has got to do something to make the ‘National Monument’ designation mean something,” the report advised. “Without it, the marine refuges will be under constant assault by the Chinese fishing fleet and a range of other sovereignty-degrading influencers.”