The president of China expressed concern about the coronavirus threat to North Korea and offered help.
Xi Jinping was responding to a message he received from North Korean leader Kim Jong-un.
Chinese state media reported that the message congratulated Mr. Xi on China's apparent success in the fight against Covid-19.
The North Korean government maintains that there has not been a single confirmed case, although analysts have questioned whether this is possible.
North Korea was the first country to suspend tourism and close its borders in response to the virus, in the third week of January.
The country has a fragile health care system, which experts fear will soon be dominated by even a small Covid-19 outbreak.
In his "verbal message of thanks," Xi said he greatly appreciated Kim's support during the outbreak in China and "showed his personal attention to the pandemic situation and people's health" in North Korea, according to state media.
Xi called for more efforts to strengthen cooperation in preventing the spread of coronavirus, and said that China is "willing to continue providing assistance in its own capacity to [North Korea] in the fight against Covid-19 ".
On Friday, North Korean state media reported that Kim sent a verbal message to the president that "congratulated him, greatly appreciating that he was seizing the chance of victory in the war against the unprecedented epidemic".
Kim recently went 20 days without appearing in public and missed his grandfather's birthday celebration – one of the biggest events of the year.
Some media reports said he was "seriously ill" or even dead.
But he appeared at a fertilizer factory on May 2 – apparently in good health.
On Wednesday, South Korea's National Intelligence Service told a parliamentary committee that there were no signs that the health rumors were true.
"He was doing his job normally when he was out of the public eye," a committee member, Kim Byung-kee, told reporters later.
The lawmaker said the absence of the North Korean leader may have been a Covid-19 outbreak that Pyongyang officials had not reported.