New satellite photos have emerged that suggest North Korea's nuclear programme is growing more quickly than first believed.

Experts claim the images show a test site in the Asian country that could soon be capable of launching a missile that could hit Alaska or Hawaii.

Satellite image firm Planet has provided the photos and say scorch marks in the ground are evidence Kim Jong-un may be testing the Hwasong-12 rocket, which is able to travel 2,500 miles, North Korea claims.

It would mean targets in Guam, Alaska and Hawaii would be within range of a nuclear attack.

New satellite images, pictured, of a North Korea nuclear test site suggest the country's missiles could be more advanced than previously thought

Scorch marks around the site, pictured, suggest the country is testing its Hwasong-12 rocket, which it claims can travel 2,500 miles, making it capable of hitting targets in Alaska and Hawaii

Jeffrey Lewis, the director of the East Asia non-proliferation program at the Middlebury Institute of International Studies, told Quartz.com tests at the site would 'continue for the foreseeable future'.

He said: 'The conclusion I draw is, it is an active nuclear weapons test site and there is stuff going on there all the time.

'On a broad level, we should be expecting tests at the site every year for the foreseeable future.'

According to the website, North Korea's missile arsenal is designed to take off from mobile launchers to evade spy cameras or surprise attacks from enemies, making it more difficult for surveillance teams.

As reported by Mail Online, Kim Jong-un has been pictured inspecting his new ballistic missile which he claims can carry a nuclear warhead before it was test-fired on Sunday.

The dictator gave the Hwasong-12 a once-over at its launch site in the Kusong region in images published by state media.

The Hwasong-12 has the longest rage of any ballistic missile the North has successfully tested, with experts estimating it can fly 2,500 miles

Kim Jong-un poses next to the Hwasong-12 intermediate-range ballistic missile, which he claims is capable of carrying a nuclear warhead, before its launch on Sunday

After the launch was deemed a success, Kim was seen laughing and celebrating with officials before vowing to carry out more nuclear and missile tests.

The missile travelled more than 400 miles before crashing into the Sea of Japan just off the Russian coast, according to the state-backed North Korean Central News Agency and South Korean analysts.

The U.S. military's Pacific Command said the type of missile that was fired was 'not consistent with an intercontinental ballistic missile'.

The White House responded to the missile test by calling for further action against Pyongyang: 'Let this latest provocation serve as a call for all nations to implement far stronger sanctions against North Korea.'

The North 'has been a flagrant menace for far too long', it added in a statement.

Meanwhile Russian President Vladimir Putin has told world leaders to stop 'intimidating' North Korea following the dictatorship's latest missile test.

Putin said attempts to bully Kim Jong-un's regime were 'unacceptable', though he admitted the missile test was equally wrong.