Chinese leader Xi Jinping is using his imminent visit to Serbia to castigate NATO for bombing the Chinese Embassy in Belgrade 25 years ago.

“Twenty-five years ago today, NATO flagrantly bombed the Chinese Embassy in Yugoslavia, killing three Chinese journalists,” Xi wrote in a letter published by the Serbian outlet Politika on Tuesday.

“This we should never forget. The Chinese people cherish peace, but we will never allow such tragic history to repeat itself,” Xi wrote.