Chinese President Xi Jinping and Russian President Vladimir Putin sent greetings to North Korean leader Kim Jong Un on the occasion of North Korea's founding anniversary, state media KCNA said on Monday.

"I am sure that the comprehensive strategic partnership between Russia and the DPRK will be strengthened in a planned way thanks to our joint efforts," Putin said, according to KCNA.

DPRK is short for the Democratic People's Republic of Korea, the North's official name.

Xi called for deeper strategic communication and cooperation with North Korea in his message, KCNA said.

Last year, Kim marked the country's founding day on Sept 9 with a parade of paramilitary groups and diplomatic exchanges in which he vowed to deepen ties with China and Russia.