New satellite images from the U.S. suggest North Korea may be preparing to launch a new missile or satellite.
The satellite launching station at Sohae was being dismantled but the process was halted when talks with the U.S. stalled.
President Trump said he would be disappointed if weapons testing restarted and, although analysts believe it is more likely to be a satellite, Washington argues that this would still be in breach of commitments made by Kim Jong-un.
The two leaders met in the Vietnamese capital last week but the talks ended when the U.S. failed to agree how far Pyongyang was expected to restrict its weapons programme before it was granted some sanction relief.
People waving flags in the North Korean capital say they fully support their leader: "We do this propaganda with the desire to give happiness to the marshal who is returning to the capital from his travels for on-the-spot guidance," said Kim Chun Hui, 47.
"So we are not tired. We regard this as our great pride and we think this is what we have to do."
The latest satellite pictures, which seem to show rebuilding work at Sohae, were provided by a number of U.S. think tanks and information from South Korean intelligence services.