Chief of Naval Operations Adm. John Richardson has ordered an operational pause of the Navy's 277 ships, including Groton-based submarines, following a collision between the Navy destroyer USS John S. McCain and an oil tanker near Singapore before dawn on Monday.

Navy divers searching one of the McCain's flooded compartments found remains of some of the 10 sailors missing, Adm. Scott Swift, U.S. Pacific fleet commander, said Tuesday as he promised a full investigation. Five sailors also were injured in the collision, which tore a gaping hole in the McCain's left rear hull and flooded adjacent compartments including crew berths and machinery and communication rooms.

It was the fourth accident involving a Navy ship in the Pacific this year, and the second collision in the past two months involving a Navy destroyer from the 7th Fleet, which is based in Yokosuka, Japan. Seven sailors died, including one from Connecticut, in June when the USS Fitzgerald and a container ship collided in waters off Japan.

"This trend demands more forceful action. As such, I direct an operational pause be taken in all of our fleets around the world," Richardson said in a video statement. "I want our fleet commanders to get together with their leaders and their commands to ensure that we're taking all appropriate immediate actions to ensure safe and effective operations around the world."

A broader U.S. Navy review will look at the 7th Fleet's performance, including personnel, navigation capabilities, maintenance, equipment, surface warfare training, munitions, certifications and how sailors move through their careers. Richardson said the review will be conducted with the help of the Navy's office of the inspector general, the safety center and private companies that make equipment used by sailors.

The Wall Street Journal reported Tuesday that the commander of the 7th Fleet, Vice Adm. Joseph Aucoin, will be relieved this week.

In the near term, Navy units worldwide have until Monday to take a one-day "operational pause" to assess basic seamanship, teamwork and readiness, essentially a safety check. These discussions will include reviewing what to do in an emergency, watch standing principles and how to evaluate risk, among other issues. Some discretion will be given to fleet commanders over how to carry out these discussions and implement the operational pause.

"As we have seen, the environments in which we operate are terribly unforgiving. As a result, we must do our utmost to ensure safe and professional operations in everything we do," said Adm. Philip Davidson, head of U.S. Fleet Forces Command, in a Navy directive calling for the review.

Cmdr. Sarah Self-Kyler, a spokeswoman for the U.S. submarine force, said the submarine fleet is undertaking the review.

A 2014 investigation by The Day found that there were 906 submarine accidents from late 2004 through 2013, though only 2 percent of those mishaps were characterized as severe, such as a collision.

The Navy-wide operational pause is "a good first step," said U.S. Rep. Joe Courtney, D-2nd District, but Congress also must look into the causes of these accidents and what can be done to prevent them.

Two congressional subcommittees, one with oversight over Navy programs and one that oversees military readiness and training, are planning a joint hearing featuring Navy witnesses and experts from the Government Accountability Office, which has been looking at the high operational Navy tempo of forward deployed ships and its impact, Courtney said. The hearing is expected to take place soon after Congress returns from its summer recess.

"There's been an overall discussion about the readiness and pace of deployments that's happening throughout the Navy and whether or not it's causing stress both in terms of personnel and equipment," Courtney said. "To that extent, there's sort of a lateral focus on whether or not things are starting to fray around the edges because of the pace of deployments."

A 2015 GAO report found that the Navy has extended deployments, increased operational tempos and shortened, eliminated or deferred training and maintenance to meet recent demand for forward presence. The service also has assigned more surface combatants and amphibious warfare ships to overseas homeports, the report says.

Associated Press writer Annabelle Liang contributed to this report.

j.bergman@theday.com