North Korea's claim that it launched a ballistic missile from a submarine was mostly likely a bluff and the images it released appear photoshopped to overstate the regime's military power, US experts said Tuesday.

Pyongyang state media announced triumphantly on Saturday that a new submarine-launched ballistic missile had been tested successfully, under the personal supervision of the country's leader Kim Jong-Un.

Kim hailed the SLBM test, saying the North had a "world-level strategic weapon."

But US defense officials have privately voiced skepticism that anything resembling a ballistic missile was test-fired. And analysts who closely follow North Korea's weapons programs are not convinced either.

"I have some serious doubts," said author Joseph Bermudez, who has written extensively about Pyongyang's missile program.

The submarine shown by the North Koreans is a prototype that was only recently put into service about six or seven months ago, and it is unlikely the vessel could already be ready to launch a missile, according to Bermudez.

Moreover, satellite photos show a barge near the submarine, which could have served as a platform to fire the missile, Bermudez said at an event organized by 38 North, a website focused on analysis of North Korea.

It is more probable that the test touted by Pyongyang was carried out from the barge, said Bermudez, who has worked as a consultant to the US military.

And as for the images of the alleged missile launch posted by the North Korean news agency, there are details that do not "match up," he said.

The images "show a bring pink shadow in the water, a reflection in the water from the missile launch," he said.

"And normally you would expect to see this if you saw a flame coming from the engine of the missile. However, there is no flame on the picture, just steam and water."

The incompatible details "might suggest that the imagery provided to the public was manipulated or photoshopped in some fashion," he said.

- New missile? -

The missile that appears in photos does not correspond to others in the North's arsenal, indicating that Pyongyang may be trying to develop a new missile to be used on submarines, Bermudez said.

The launch likely involved a prototype missile, built specifically for an ejection test, said Joel Wit, a former US diplomat.

Despite the North's overblown claims, the regime's bid to construct an arsenal of submarine-launched missiles is no joke, said Wit, the co-founder of the 38 North site.

Pyongyang is determined to build an eventual sea-based arsenal, but the regime has presented it as more advanced than it really is, he said.

A North Korean fleet of submarines capable of launching ballistic missiles represents a strategic nightmare for the United States and its Asian allies. It would transform the danger posed by the North, allowing it to carry out a nuclear strike from distant locations or to retaliate in the event of a nuclear conflagration.

Apart from its submarine-based efforts, Pyongyang has already conducted three nuclear tests and is working to place atomic warheads on missiles.

Shortly after the Cold War, North Korea purchased submarine missile technology from Moscow and has tried to reverse-engineer old Russian subs to construct a launch system, according to John Schilling, an aerospace engineer who has written about Pyongyang's missile work.

If it could muster enough money and receive badly needed outside technological help, North Korea might be able to develop submarine-launched missiles by 2020, Wit said.

Even in that scenario, the weapons would not pose a risk to the United States but to neighboring countries such as South Korea or Japan, because Pyongyang has yet to successfully build a long-rang ballistic missile that could reach American territory.

Wit said those submarines "would be more of a regional threat."

If the North attempted to deploy subs near the US coast, the vessels would be easily countered by sophisticated American anti-submarine radar and weapons.

"I wouldn't want to be on one of those subs, because I don't think they could get even close," said Wit.