China's President Xi Jinping took a swipe at Nato's past actions on Tuesday despite a French charm offensive on a rare visit to Europe.
Mr Xi said China would "never forget" the bombing of its embassy in Belgrade in 1999 during Nato air strikes in Yugoslavia.
He invoked what he called that "tragic history" as like-minded Serbia prepares to welcome Mr Xi for a state visit.
His article in Serbian media appeared as Mr Xi was accompanying French President Emmanuel Macron for private talks in the Pyrenees.
Europe is lobbying Mr Xi to use China's ties to Russia and Iran to restrain their actions in Ukraine and the Middle East, respectively.
Mr Macron discussed Iran and the Middle East with Mr Xi before taking the Chinese leader to the mountain air of the Col du Tourmalet.
The two leaders took separate flights to the Pyrenees before watching a traditional dance routine and eating local delicacies in an area where a young Mr Macron spent holidays.
The French President has a history of trying to forge close personal relationships with his counterparts but has a mixed record of extracting concessions from them.
While Mr Xi spoke warmly of China's relations with France, he offered few hints of concrete concessions in his talks in Paris on Monday.
China "did not start the Ukraine crisis, nor is it a party to or a participant in it" and opposes attempts to "stoke a new Cold War", he said.
He also denied there was any Chinese "overcapacity problem", a key grievance for European officials in trade talks.
The second and third legs of Mr Xi's trip will take him to Serbia and Hungary, regarded as two of the most Moscow and Beijing-friendly governments in Europe.
In his article for a Serbian audience, Mr Xi spoke of an "ironclad friendship" as he recalled the deaths of three people in the Chinese embassy bombing that took place 25 years ago on Tuesday.
Nato called the May 1999 bombing a "deeply regrettable mistake" during an air campaign meant to stop ethnic cleansing in Kosovo.
An envoy for then-US president Bill Clinton was sent to explain how a CIA agent had mistaken the embassy for a Yugoslav weapons centre.
"Twenty-five years ago today, Nato flagrantly bombed the Chinese embassy in Yugoslavia, killing three Chinese journalists," Mr Xi said.
"This we should never forget. The Chinese people cherish peace but we will never allow such tragic history to repeat itself."
Serbia aspires to EU membership but still bristles at the Nato bombing campaign and has maintained close ties to Russia and China.
Hungary is meanwhile briefing before Mr Xi's visit that it "rejects protectionist efforts to exclude Chinese goods from the European market", for example welcoming ties with telecoms giant Huawei.
