From a possible cyber attack to a technical failure that could have jammed the ship's steering, nothing is being ruled out in the probe to determine what caused a US warship and an oil tanker to collide in the Singapore Strait on Monday.
While he declined to comment on specifics, given the early stage of the investigations, Admiral Scott Swift, commander of the United States Pacific Fleet, said he was aware of the theories going around.
Speaking to reporters at Changi Naval Base last evening, Adm Swift said he has heard of media reports that the collision could have been caused by a cyber attack.
While there have been "no indications of that as of yet", he added that the US Navy is "not taking any consideration off the table, and every scenario will be reviewed and investigated in detail".
This includes possible negligence, he said, which will be investigated. "Along with responsibility and authority come accountability, and I think the record of the United States Navy is clear on that."
While he did not elaborate, observers said he was likely referring to three other recent collisions involving US warships, including an earlier incident in June.
Seven sailors died when the USS Fitzgerald - also part of the 7th Fleet - collided with a container ship off Japan. The US vessel's captain was stripped of his command after the navy found that flaws in keeping watch could have contributed to the accident.
"We will conduct a thorough and full investigation into this collision - what occurred, what happened, and how it happened... One tragedy like this is one too many, and while each of these four events is unique, they cannot be viewed in isolation," Adm Swift said yesterday.
He added that he would work with US Chief of Naval Operations John Richardson to find out if there was a common cause at the root of these events and to solve that, if so. The US Navy has ordered fleet-wide investigations to review processes and identify gaps, but commanders are to space out the review to avoid hampering operations.
But Adm Swift was quick to dismiss suggestions that crew fatigue could have played a part.
"I don't think that is the case at all. I was on McCain this morning, looking at the eyes of those sailors. Even after their heroic efforts yesterday, I didn't see exhaustion."
Asked if the spate of collisions should raise worries over the Pacific Fleet's ability to respond to threats, Adm Swift said he was not at all concerned, citing its "deep bench of 140,000 reporting to duty every day" who can respond to any guidance from the top brass.
Apart from the 10 missing US sailors, another five were injured, with four of them medically evacuated by a Singapore Armed Forces helicopter to Singapore General Hospital. The fifth did not require further medical attention.
US Vice-President Mike Pence, who spoke to Fox News, said having sailors killed in two collisions this year was disconcerting. "It is just unacceptable, and we will get to the bottom of it.... But right now, our hearts are with the families of those that are lost, and we honour them."
The US warship, which was en route to Singapore for a routine port call, is now berthed at Changi Naval Base. The Liberian-flagged tanker is berthed at Changi's eastern anchorage to be further assessed.
Stealth Maritime Corporation, which manages the tanker, told The Straits Times its all-Filipino crew were "safe and well" and have remained on board. A spokesman said: "The Master, and indeed all the crew, are cooperating fully with a number of investigations. Obviously, the MPA (Maritime and Port Authority of Singapore) investigation is paramount, but there are a number of other investigations too."
• Additional reporting by Zaihan Mohamed Yusof
