North Korea has started pulling cables from tunnels at its nuclear testing site, US Intelligence says.

The separation of the cables at the Punggye-ri nuclear test site is believed to be the first step towards shutting down the country's nuclear program, CBS reported.

Just days ago, landmark meetings with South Korean President Moon Jae-in resulted in North Korean leader Kim Jong-un vowing to shut down the testing facility completely in May - with the process to be opened to US and South Korean experts and journalists.

Pictured: The Punggye-ri nuclear test site, where North Korea is reportedly pulling cables as it prepares to dismantle its nuclear program

The sudden change came after historic meetings between North Korea's leader Kim Jong-un and South Korean President Moon Jae-in last week (pictured)

The pair met at a border truce village, signalling the first time a North Korean leader had ever stepped over the military demarcation line since the nation.

During the meeting, they discussed formally ending the 1950-53 war between the two countries and the end of North Korea's nuclear program.

US President Donald Trump is expected to meet with Kim in May or June, where more regimented plans for the nation's denuclearization are expected to be formed.

The location of the meeting is yet to be announced, with Trump recently asking Twitter followers if they believed Peace House, on the border of North and South Korea, will be a more 'Representative, Important and Lasting site than a third party country?'.

Trump's deputy press secretary on Tuesday said that his preference is the demilitarized zone, or DMZ - the same location where Kim and Moon met last week.

But the President walked back the suggestion at a press conference on Monday, saying: 'Well it was an interesting thought. And I had that thought'.

During the meeting, the Presidential office in Seoul claims Jong-un promised he would dismantle his nuclear program this month

North Korea is expected to engage in talks with US President Donald Trump in May or June to form a more substantial plan to disarm the country

'We’re looking at various countries, including Singapore, and we are also talking about the possibility of the DMZ – Peace House, Freedom House,' he said.

'There’s something that I thought was intriguing... there’s something that I like about it because you’re there. You’re actually there.'

'Where if things work out there’s a great celebration to be had on the site, not in a third party country. So we are looking at the possibility of doing it in that location.'

For the summit with Trump to happen, the U.S. says that North Korea must publicly and verifiably prove that it has given up its nuclear weapons.

The meeting between Jong-un and Jae-in is the first time a North Korean leader has ever stepped over the military demarcation line

North Korea has reportedly agreed to invite journalists and experts from the US and South Korea witness the denuclearization process