The U.S. government has a new battle in Vieques, the Puerto Rican island that was used as a Navy bombing range for decades.

An extensive cleanup of Vieques is underway and the Navy says is close to finishing work on a former munitions disposal site on the island. It would be a milestone for the cleanup but it the plan has sparked criticism.

The government proposes fencing off the 400-acre site as a nature reserve, without clearing about half the area of debris from years of detonating out-of-date munitions. The Navy says it poses little danger and protects habitat.

Opponents say the Navy should clear the entire area. The plan is still under review. A public comment period ends Friday.