Trump tweeted that "the reason I do not want military drills with South Korea is to save hundreds of millions of dollars for the U.S. for which we are not reimbursed".
Commercial satellite images of North Korea's rocket facility in Sanumdong suggest that Pyongyang may be preparing to launch a missile or space rocket in a short time, the US-based NPR radio station reported, publishing one of the pictures.
"The area that we fell most short was on denuclearisation and it was clear to us that our North Korean interlocutors had very little authority to move on the set of issues that were, in our view, central to the success of this outcome", the official said.
Melissa Hanham, a North Korea expert with the One Earth Future Foundation, said the increase in activity at the site shows that the two countries are "moving farther apart rather than closer", with regards to nuclear talks. They show trucks and cars parked nearby, while rail cars sit in a yard, where two cranes are erected, it said.
"In the past there have been multiple reports about activity at this place that turned out to be false alarms", Wit said, referring to Sanumdong.
The UN imposed sanctions on North Korea after it launched satellites from Sohae, which were regarded as a disguised test of missile technology. A senior US State Department official said on Thursday that any launch from there would be "inconsistent" with North Korean commitments.
The Sohae Launch Facility satellite images were taken on March 2, just days after the Hanoi summit's collapse, showing that the site is back under construction.
US Air Force B-1B bombers, F-35B stealth fighter jets and South Korean F-15K fighter jets fly over the Korean Peninsula during joint drills on September 18, 2017.
'I think US foreign policy has been far too obsessed with North Korean space launches, ' he added. "They will not test ideas at the negotiating table", he said.
The news seemed to surprise Trump, who has made a detente with North Korea and forging a personal relationship with Kim a signature element of his foreign policy. The U.S. has it in its power to achieve North Korean denuclearization after all.
Our correspondent adds that experts say the rockets used to launch satellites are usually unsuitable for use as long-range missiles.
This week's satellite images, coming from several USA think tanks and testimony from the South Korean intelligence service, appear to show rapid progress has been made in rebuilding structures on the rocket launch pad.
"The public at home and overseas that had hoped for success and good results from the second DPRK-US summit in Hanoi are feeling regretful, blaming the US for the summit that ended without an agreement", KCNA reported, citing a commentary in the Rodong Sinmun newspaper.
What's more, the breakdown in Hanoi has cast a shadow on each of Japan, the USA and South Korea. It cited Kim as saying North Korea and the United States must put an end to their decades-long animosity and confrontation.
Trump's envoy to North Korea, Steve Biegun, had lunch Wednesday at the State Department with his counterparts from Japan and South Korea.
She said the images are more likely connected to a satellite launch than any military missile activity.