PYONGYANG, North Korea -- New satellite images show that North Korea may be preparing to conduct its sixth nuclear test. A U.S.-based watchdog group says the country is “primed and ready” after analyzing telltale signs of activity at the remote underground test site.

Satellite images show activity at a North Korea nuclear facility 38 North

Exploding a more powerful bomb, or launching a new ballistic missile, could be timed to coincide with this weekend’s celebration of North Korea’s founder -- often marked by a massive parade in which the country is not subtle about showing off its military might.

Kim Jong Un, the current North Korean leader, made an appearance in Pyongyang Thursday in front of a crowd so large it appeared to be everyone who lives in the city.

He cut a ribbon to officially open a newly built neighborhood with more than a dozen new high rises, some 70 stories tall. It was an attempt to show economic progress in a country where the reality is that most people live in poverty.

Kim Jong Un at a ribbon-cutting ceremony in Pyongyang CBS News

Kim did not speak at this event, but he didn’t have to; He let the buildings do the talking. His message to America: your sanctions don’t work and we will keep building our buildings and our missiles.

North Korea’s goal is a nuclear-tipped intercontinental ballistic missile capable of reaching the United States, which experts now say they could accomplish in the next few years.

That threat has become one of the most serious issues facing the Trump administration. In a tweet Thursday, President Trump once again called on China to rein in North Korea or said the U.S. will do it.