Just days ago they were at the centre of a possible nuclear war as Trump threatened to strike Kim Jong-un if he carried out a sixth nuke test.

But things have since calmed down at North Korea's Punggye-ri nuclear test site, as staff were pictured playing what seems to be games of volleyball.

These satellite images were captured on Sunday, a day after the communist state's Day Of The Sun celebrations, by monitoring group 38 North.

Staff at North Korea's Punggye-ri nuclear testing site were photographed by satellite on Sunday while apparently having a game of volleyball

These images were taken on Sunday, just 24 hours after the Day of the Sun celebrations when many expected Kim to use the site to carry out a sixth nuclear test

Trump had hinted that another test would cause him to launch pre-emptive strikes against North Korea, with this site a likely target

They seem to show the base has been put into standby mode, with workers relaxing and equipment left in place after weeks of increased activity.

Punggye-ri was widely expected to be the site of a sixth nuclear test over the weekend to mark North Korea's founding.

However, President Trump had warned despot Jong-un that carrying out another explosion at the underground base would prompt pre-emtive strikes.

Top of the list would likely have been the Punggye-ri facility.

To reinforce his message, Trump diverted the Carl Vinson carrier strike group to the region, sending the USS Nimitz and USS Ronald Reagan in after it.

It has since emerged that none of the carrier groups mentioned were in the region at the time, though they are making their way there now.

Experts had warned for weeks of increased activity at the site, where nuclear explosions are carried out underground before being studied with testing equipment

Punggye-ri appeared to have been put on standby following Day of the Sun celebrations, with equipment unmoved and vehicles moved away from the tunnels

Kim Jong-un has made it his mission to develop a small but powerful nuclear device that could be fitted to a missile with enough range to reach the mainland United States

Trump has described the force as an 'armada' and warned Kim he 'must behave' if he doesn't want it to be used against him.

For his part, the North Korean leader has kept up his typically aggressive rhetoric, saying on Thursday that it is prepared to carry out a 'super-mighty preemptive strike' and warning America: 'Don't mess with us.'

State controlled media claimed its military could 'immediately wipe out the US mainland' and reduce its enemies 'to ashes'.

It has also emerged that Vladimir Putin is reinforcing his border with North Korea by relocating troops and equipment, after China deployed 150,000 troops on its border.

After drawing the world's attentions with a strike on Syria, President Trump had issued a stark warning to Kim Jong-un not to carry out more tests, saying he has 'got to behave'

The move was interpreted by many as being preparations for an influx of refugees if war had broken out with the US.

Video purports to show one of three trains loaded with military equipment moving towards the 11 mile-long land frontier between Russia and the repressive state in Russia's far south east.

Another clip highlights military helicopter movements towards the North Korean border and manoeuvres across rough terrain by army combat vehicles. Other reports suggest there have been military moves by road as well.

There have been concerns that if a conflict breaks out Russia could face a humanitarian exodus from North Korea.