The sub was spotted allegedly cruising above the surface of the waters separating Taiwan from mainland China, where many analysts say conflict is more likely to start from an accidental collision than a planned event — and the more warships in a confined space, the more chances there are for accidents to happen.
The reason for its alleged presence in the strait is unknown, but Sutton said it was likely the Chinese sub — also known as an SSBN or boomer — was on a routine mission, possibly heading back to a People’s Liberation Army (PLA) Navy port on the Bohai Sea for repairs or maintenance.
But other experts who viewed the satellite image said the alleged presence of a boomer on the surface was perplexing.
“An SSBN on the surface is all but unheard of,” said Carl Schuster, an ex-US Navy captain and former director of operations at the US Pacific Command’s Joint Intelligence Center. “This may suggest a hull or engineering problem that requires a major shipyard to investigate and fix.”
The Taiwan Strait is just 110 miles (180 kilometers) across at its narrowest point. It has become one of the world’s military hotspots as China puts increasing pressure on self-governed Taiwan, which Chinese President Xi Jinping has vowed to bring under Beijing’s control. In response, supporters of the government in Taipei, including the United States, have stepped up their military presence in the region.
This week, the commander of the US Navy’s 7th Fleet, headquartered in Japan, said more US and partner aircraft carriers are needed in the western Pacific.
Vice Adm. Karl Thomas, speaking on board the aircraft carrier USS Carl Vinson after large-scale naval exercises involving the US, Japan, Australia, Canada and Germany, said aircraft carriers make a big statement of deterrence.
Meanwhile, China — which already boasts the world’s largest navy by number of ships — is continuing to churn out new naval vessels.
Stepped-up US and Chinese military ship and aircraft operations in the South China Sea “could increase the risk of a miscalculation or inadvertent action that could cause an accident or lead to an incident that in turn could escalate into a crisis or conflict,” the report said.
Japan in October launched the second boat in its new class of diesel-electric submarines. The first in the Taigei class is expected to be commissioned in March.
While there has been no indication the alleged Chinese sub spotted Monday suffered an accident, “it is an interesting mystery,” said Schuster, who also noted the PLA could have simply been showing its muscle in the strait, as the US and its partner navies have done recently.
CNN has reached out to Chinese Ministry of Defense and Ministry of Foreign Affairs for comment.