The commander of U.S. naval operations has ordered a comprehensive review to get to root causes after the collision this week between a Navy destroyer and an oil tanker near Singapore.

Monday’s early-morning crash is the latest “in a series of incidents in the Pacific theater,” Adm. John Richardson said in a video statement. “This trend demands more forceful action.”

Navy ships have been in at least four accidents in the Pacific this year:


JAN. 31: USS ANTIETAM

The commander of the USS Antietam was relieved of duty after the guided-missile cruiser ran aground while it was anchoring near Yokosuka base, the home port of the U.S. Navy’s Japan-based 7th Fleet.

The ship’s propellers were damaged, and it returned to Yokosuka with the help of tugboats, the Navy said. About 1,100 gallons (4,000 liters) of hydraulic fuel leaked into Tokyo Bay, according to media reports.

Capt. Joseph Carrigan was removed from command about a month later.

Stars and Stripes newspaper said an investigation report it obtained under the Freedom of Information Act describes a series of errors and incorrect judgments leading to the grounding.


MAY 9: USS LAKE CHAMPLAIN

A South Korean fishing boat collided with the USS Lake Champlain guided-missile cruiser off the Korean Peninsula.

No one was injured, and both ships were able to sail away under their own power, the Navy said.

The Champlain sounded its horn and tried to contact the fishing boat, but the latter did not have a radio, the U.S. Naval Institute News website said, citing an unnamed Defense official.

The San Diego-based Champlain was operating in the western Pacific for the first half of the year as part of the 3rd Fleet’s USS Carl Vinson aircraft carrier strike group.


JUNE 17: USS FITZGERALD

Seven sailors died after a container ship collided with the USS Fitzgerald guided-missile destroyer off Japan.

The collision tore a gash into the side of the Yokosuka-based ship, flooding sleeping quarters and other areas.

The cause remains under investigation, but the Navy relieved the ship’s commanding officer and two other senior officers on Friday, just three days before the latest collision.

The Navy said “the collision was avoidable and both ships demonstrated poor seamanship.”


AUG. 21: USS JOHN S. McCAIN

Ten sailors are missing after the USS John S. McCain guided-missile destroyer collided with an oil tanker near Singapore.

The collision left a gaping hole in the destroyer’s hull, flooding adjacent compartments including crew berths and machinery and communications rooms.

There was no immediate explanation for the collision. Singapore, at the southern tip of the Malay Peninsula, is one of the world’s busiest ports and a U.S. ally, with its naval base regularly visited by American warships.