China will reinforce “strategic communication and boost coordination” with North Korea, Chinese President Xi Jinping wrote in a letter to Kim Jong Un, marking just the second-known correspondence between the two leaders amid signs of strained bilateral ties.

According to the Korean Central Network Agency (KCNA) on Monday morning, Xi delivered the message while sending greetings to Kim to celebrate the 76th DPRK National Founding Anniversary.

The Chinese leader reportedly wrote that Beijing will develop “the traditional China-DPRK friendly and cooperative relations by deepening the strategic communication and boosting coordination and cooperation.”

“Under the new situation in the new period,