South Korean officials say analysis of debris from the latest North Korean rocket shows it has the ability to reach the US mainland.

At a news conference in Seoul on Sunday, Defense Ministry officials made the announcement after their experts looked at parts of the rocket that fell in the sea after Pyongyang’s successful launch on Dec. 12.

They have only recovered part of the first stage of the rocket from the Yellow Sea off South Korea’s West Coast.

But that has shown them, they believe, that North Korea now has the ability to fire it.

Their estimate comes from analyzing an oxidizer container, which stored red fuming nitric acid to fuel the first-stage propellant.

“Based on our analysis and simulation, the missile is capable of flying more than 10,000 kilometers (6,200 miles) with a warhead of 500-600 kilograms,” a defense ministry official told reporters.

South Korean missile experts believe the use red fuming nitric acid shows it was an intercontinental missile test.

“Red fuming nitric acid was used in missiles developed by the Soviet Union,” said a member of the South Korean Defense Ministry team.

“Because it used red fuming nitric acid as an oxidizer, which can be stored for a long time at normal temperature, the team concluded that (the rocket) was intended for testing (the North’s) ICBM technology, rather than developing a space launch vehicle.“

The analysis will give support to the argument by America and its allies that they believe North Korea the rocket launch was an attempt to test an inter-continental ballistic missile rather than, as Pyongyang maintains, part of a space program.

South Korean Defense officials say though its impossible to determine if North Korea has developed re-entry capability, a key element of an inter-continental ballistic missile, until they recover parts of the second and third stages of the rocket.

Defense experts believe Pyongyang has shown with the successful launch of an object into space via a three-stage rocket that it has moved a major step forward in developing inter-continental missile technology.

“In technological terms, the launch moves North Korea a major step closer to developing an inter-continental ballistic missile. It demonstrates the successful development of a three-stage rocket design, which, although not a ballistic missile,” James Hardy, Asia Pacific Editor, IHS Jane’s Defense Weekly told Fox News.

Its widely thought that it will be many years before North Korea can develop a long-range missile that can carry a nuclear warhead but it has surprised many by its ability with its latest rocket launch.

Even if a nuclear threat to the US West Coast may be far in the future there is a real danger now that Pyongyang will press ahead with an attempt to develop a shorter range missile that can carry a nuclear warhead.

Jim O'Halloran, a weapons analyst with IHS Jane’s, told Fox News that “this particular missile bears no direct threat to the US continent and indeed will be some time, probably many years, before this could happen."

“It will on the other hand give rising concern to North Korea’s neighbors in that they must now start addressing their previous concerns about how long it will take the North Koreans to develop long-range missile technology into some kind of intermediate/long-range ballistic missile that can carry a warhead that can threaten those countries.”

While there were mass celebrations in North Korea following the successful rocket launch it only raised tensions in the region that was already reeling from rows over disputed islands between China, Japan and South Korea.

Even the celebration of Christmas has now become part of the tense Korean standoff.

About 100 Christians attended the ceremony to light up a giant Christmas tree this weekend near the border with North Korea.

It was an annual ritual that was stopped back in 2003 to try to improve relations between the two countries.

But it has now resumed following a deadly artillery attack by North Korea on a South Korean island.

Pyongyang says the tree is psychological warfare and has nothing to do with Christmas and could cause more conflict.