A USA aircraft carrier and its strike group will arrive off the Korean Peninsula at the end of this month.
Admiral Harry Harris, commander of the U.S. Pacific Command, had announced April 9 he was ordering the strike group to sail north after leaving Singapore and that it would not be making previously planned port visits in Australia.
A senior administration official was also quoted as telling CNN that it was because of a miscommunication.
North Korea had just launched a Scud extended-range missile, only the latest in a series of launches by the rogue state in the first four months of 2017.
Singapore-based security expert Ian Storey said countries in the region would have found the confusion over the strike group's location "unsettling and perplexing".
Speaking to US and Japanese troops on board the USS Ronald Reagan aircraft carrier Wednesday, he called North Korea the most urgent and risky threat to the peace and security of the Asia-Pacific region. He visited South Korea earlier and will head to Indonesia after his stop in Japan.
"I actually have to give credit to the White House because you have a China that is more engaged than ever before in North Korea", he said.
An aircraft carrier strike group that the Trump administration had said was headed toward North Korea in a powerful show of force has instead spent the past week thousands of miles away - and heading in the opposite direction.More news: Samsung reveals Galaxy S8, S8 Plus
And the announcement that the Vinson had been dispatched to the region increased tensions with Pyongyang, with its official Korean Central News Agency calling the carrier's deployment "nothing but a reckless action of aggression to aggravate the tensions in the region".
It was supposed to be steaming towards North Korea more than a week ago, an "armada" signaling American resolve.
"US Pacific Command ordered the Carl Vinson Strike Group north as a prudent measure to maintain readiness and presence in the Western Pacific", said Commander Dave Benham, spokesman at US Pacific Command.
The photos are dated between April 10th and 11th.
In Riyadh, Saudi Arabia, Mattis said: "The bottom line is in our effort to always be open about what we were doing we said that we that we were going to change the Vinson's upcoming schedule".
He said, "I hope there will be no unilateral actions like those we saw recently in Syria and that the USA will follow the line that President Trump repeatedly voiced during the election campaign".
China has also cautioned North Korea against going for sixth nuclear test defying USA warnings.
But on Saturday, a full week after the initial news release, the Navy posted a photograph showing the Carl Vinson transiting south through the Sunda Strait between the Indonesian islands of Sumatra and Java - about 3,500 miles southwest of the Korean Peninsula.