The deadly incidents involving the USS John S. McCain this week and USS Fitzgerald in June call for thorough investigations to restore confidence in a Navy considered the world's best, analysts said.

There were two more minor accidents involving Navy warships earlier this year. A commander said the four "cannot be viewed in isolation." The Navy has ordered an "operational pause," which one analyst said makes sense "to explore what on Earth is happening."

The incidents have sparked concerns that the U.S. Navy could be overstretched in Asia -- both ships were from the Japan-based Seventh Fleet -- as they tackle China's rising assertiveness and North Korea's nuclear ambitions.

It is still unclear how the collision occurred early Monday between the USS McCain and a tanker off Singapore, leaving 10 American sailors missing and five injured.

It was the second major collision in two months involving the Pacific-based 7th Fleet, and the Navy has ordered a broad investigation into its performance and readiness. Seven sailors died in June when the USS Fitzgerald and a container ship collided in waters off Japan. There were two lesser-known incidents in the first half of the year. In January, the USS Antietam guided missile cruiser ran aground near Yokosuka base, the home port of the 7th Fleet, and in May another cruiser, the USS Lake Champlain from the Navy's 3rd Fleet, had a minor collision with a South Korean fishing boat.

Divers searching for 10 missing sailors on a U.S. destroyer that collided with a tanker off Singapore have found human remains, the commander of the U.S. Pacific Fleet said yesterday. "The divers were able to locate some remains in those sealed compartments during their search today," Admiral Scott Swift told reporters, referring to a search by divers of compartments of the damaged warship USS John S. McCain. He said Malaysian authorities, involved in the three-nation air and sea search for the sailors, had also found a body and it was being transferred to the U.S. Navy for identification.

The McCain had been heading for a routine stop in Singapore after carrying out a "freedom of navigation operation" in the disputed South China Sea earlier in August, sparking a furious response from Beijing. On Monday the Chief of US Naval Operations Admiral John Richardson ordered commanders within a week to set aside time, perhaps "one or two days", for crews to sit down together for discussions. A "comprehensive review" of practices would also begin.

The damaged vessel is named after US Senator John McCain's father and grandfather, who were both admirals in the US navy. The tanker involved in the collision, which was used for transporting oil and chemicals and weighed over 30,000 gross tons, sustained some damage but no crew were injured.