Weapons experts are one in expressing alarm at North Korea's ambition after it tested a long-range rocket system over the weekend that drew worldwide scorn, reports said.

According to The Heritage Foundation, North Korea's new Taepodong 3 missile has an estimated range of 13,000 kilometres. As such, if fitted with a nuclear warhead the missile could hit any target in the entire continental U.S., unleashing a doomsday scenario with millions of people killed and large areas destroyed.

North Korea continued to claim that the rocket it tested only placed a satellite in orbit as part of its peaceful space programme.

However, many weapons experts believe that Pyongyang's latest action is just a cover for testing a ballistic and nuclear weapons programme, according to Business Insider.

Writing for The Daily Beast, Gordon Chang says the satellite system North Korea claims to have launched over the weekend could "dovetail" with Pyongyang's earlier claim of having successfully tested and detonated a miniaturised hydrogen bomb.

"If its warhead is nuclear and explodes high above the American homeland, an electromagnetic pulse could disable electronics across vast swatches of the country," Chang writes. Such a scenario could unleash unimaginable horror on America.

Last October, Admiral Bill Gortney, commander of the North American Aerospace Defense Command, also warned that North Korea already has "the capability to reach the [US] homeland with a nuclear weapon from a rocket," The Guardian reported.

Gortney earlier warned in April 2015 that based from the Pentagon's assessment, North Korea already has the capability to place miniaturised nuclear warheads on its KN-08 intercontinental ballistic missile.

Gortney, however, assured that even if North Korea fires such a missile aimed at a U.S. target, America's anti-missile rocket system could safely destroy it in the air above the sea. "Should one get airborne and come at us, I'm confident we would be able to knock it down," he told reporters.

Faced with the North Korean challenge, the US has deployed the Terminal High Altitude Area Defense (THAAD) missile system to South Korea.

According to the Pentagon, that anti-missile system is built to knock enemy missiles out of the sky, thus neutralising North Korea's threat to launch long-range missiles directed at the U.S.

Pentagon's optimism, however, could not stop weapons experts from warning of the potential harm that a North Korean attack could unleash on America.

In January this year, top weapons expert Peter Pry said the results of the nuclear test conducted by Pyongyang that month were in keeping with the expected after effect following the detonation of an electromagnetic pulse (EMP) weapon, which is "another kind of hydrogen bomb."

Pry told WND that what the North Koreans just tested had all the hallmarks of a super-EMP explosion, which produces enhanced amount of devastating gamma rays despite its low yield.

He said such a weapon could be triggered to explode on command at a high altitude over a highly populated area in the U.S.

The explosion and the resulting gamma ray emissions would result in the destruction of food supply chains, fuel supply systems, communications, banking and all other grid-dependent systems, he warned.