Connecticut: The American nuclear submarine damaged last month in the South China Sea hit an uncharted seamount, an explanation that would ease concerns that it had collided with a foreign vessel in the contested waterway. An investigation into the October 2nd collision involving the USS Connecticut found the submarine had struck a previously unknown submerged feature. The matter has been sent to Vice Admiral Karl Thomas, the Seventh Fleet commander, for review whether further actions are warranted.

In response to a question Tuesday, China’s foreign ministry repeated its demand for a “full account” of what happened, citing concerns about the crash’s location, any possible nuclear leakage and damage to the marine environment. “This fully shows the irresponsibility of the U.S.,” Foreign Ministry spokesman Wang Wenbin told a regular news briefing in Beijing. 11 sailors were injured in the incident, which damaged Connecticut’s forward ballast tanks and forced the crew to make a weeklong voyage on the surface to return to port.

The vessel is currently in Guam undergoing repairs, and the U.S. Navy has repeatedly said the nuclear reactor and propulsion system were not affected in the incident. The Navy’s surface fleet has suffered several accidents in the Western Pacific, including back-to-back collisions involving two guided-missile destroyers in 2017, prompting the dismissal of the Seventh Fleet’s commander and investigations into naval training, policies and equipment. The latest incident had caused renewed attention about a backlog in maintenance for the U.S.’s attack submarine fleet.