Tong Zhao, a North Korea expert at the Carnegie Tsinghua Center for Global Policy in Beijing, said Pyongyang “wants to have some insurance against this upcoming summit meeting with President Trump.”

“They know the meeting is very important but also very risky, there are a lot of uncertainties,” he said. “If the meeting fails the US could declare that diplomacy has failed and shift to a more coercive approach or even a military strike.”

“A stable and positive relationship with China would prevent the US from launching a military strike,” Zhao said.