The speed with which Kim Jong-un ordered the reconstruction of the Tongchang-ri rocket launching site after the failure of his talks with Donald Trump demonstrated a calculated move designed to test the US president.

Although the restoration does not breach any pledge made by North Korea about suspending missile flight-testing, it is a very overt message that Pyongyang has the ability to produce and launch effective weapons, and that these will not be given up unless the US is prepared to pay a suitably high price.

One now has to watch what Pyongyang does after the test stand is rebuilt. Satellite images show that efforts have been made to restore a “transfer building”, a mobile structure used to place a rocket to a launch tower, and there are also signs that the launch tower itself has been rebuilt.

Tongchang-ri has, in the past, been used to launch two satellite-bearing rockets and the technology has been valuable in building missiles. Any sign that the site is being prepared for missile test-firing would put great pressure on Trump to take action.

The Washington-based think tank, the Centre for Strategic and International Studies (CSIS), which obtained and analysed the images of the site development, concluded that Pyongyang’s actions were “deliberate and purposeful” and intended “to demonstrate resolve in the face of US rejection” of the proposals Kim Jong-un had made at Hanoi.

North Korea's pervasive leaders: the Kim portraits Show all 16 1 /16 North Korea's pervasive leaders: the Kim portraits North Korea's pervasive leaders: the Kim portraits In the Democratic People's Republic of North Korea, portraits of former supreme leaders Kim Il Sung and Kim Jong Il are required by law to be hung in the home, the classroom, the factory and all manner of other private and public places Reuters North Korea's pervasive leaders: the Kim portraits In the classroom AFP/Getty North Korea's pervasive leaders: the Kim portraits In the living room AFP/Getty North Korea's pervasive leaders: the Kim portraits In the maternity ward of the hospital Alamy North Korea's pervasive leaders: the Kim portraits On board the ship Reuters North Korea's pervasive leaders: the Kim portraits At the ballot box Mannen av börd North Korea's pervasive leaders: the Kim portraits In the office AFP/Getty North Korea's pervasive leaders: the Kim portraits On the bridegroom Reuters North Korea's pervasive leaders: the Kim portraits On the Pyongyang subway Reuters North Korea's pervasive leaders: the Kim portraits On a government building Reuters North Korea's pervasive leaders: the Kim portraits In the teacher training facility AFP/Getty North Korea's pervasive leaders: the Kim portraits In Kim Il Sung square in Pyongyang Reuters North Korea's pervasive leaders: the Kim portraits In the home AFP/Getty North Korea's pervasive leaders: the Kim portraits At the military parade Reuters North Korea's pervasive leaders: the Kim portraits In the hall Reuters North Korea's pervasive leaders: the Kim portraits At the Chinese border AFP/Getty

An overly confrontational stance by North Korea would, however, give senior figures in the US administration, who have been sceptical of the talk process from the beginning, ammunition to press for punitive action.

John Bolton, Trump’s national security advisor, has been the leading hawk on this issue. He had suggested that Kim Jong-un follows the “Libyan model” of denuclearisation under which Col Muammar Gaddafi gave up his nuclear arsenal to be allowed back into the international fold. Eight years later, of course, Nato bombing led to the overthrow, capture and lynching of the Libyan leader by rebels.

Bolton’s suggestions led to howls of outrage in Pyongyang and Trump appeared to distance himself from his national security advisor. But the collapse of the Hanoi summit has strengthened the hands of the sceptics – and the news about the launch site has added to that.