Chinese officials demanded extensive “details” about a collision involving a U.S. nuclear submarine in the South China Sea, which Beijing cited to continue arguing against American military operations in a region that the rising communist power seeks to dominate.

“We are gravely concerned about the incident,” Chinese Foreign Ministry spokesman Zhao Lijian told reporters, per the official transcript. “As the party involved, the U.S. should clarify in specific details what happened, including the exact location of the incident, the U.S. side’s navigation intention, the details of the incident, the object the submarine struck, whether the collision caused a nuclear leak or damaged local marine environment, etc.”