North Korea says the leaders of Russia and China have sent North Korean leader Kim Jong Un messages of congratulations on the country's 76th founding anniversary.

The ruling Workers' Party newspaper, the Rodong Sinmun, reported on Monday that large celebrations were held in central Pyongyang on Sunday, one day before the anniversary.

The paper says Russian President Vladimir Putin referred to his June summit with Kim in his message to the North Korean leader. Putin wrote he is sure that the comprehensive strategic partnership between the two countries will be strengthened in a planned way thanks to their joint efforts.

The paper says Chinese President Xi Jinping also sent Kim a message. Xi wrote that this year marks the 75th anniversary of the establishment of diplomatic relations between the two countries. He stressed that Beijing will deepen strategic communication with Pyongyang.

The news report is apparently aimed at highlighting the strengthening of North Korea's ties with China and Russia, amid deepening security cooperation among Japan, the United States and South Korea.

But South Korea's Yonhap News Agency says Xi's message -- the first in eight months -- came as relations between Pyongyang and Beijing have become relatively estranged, in contrast to Pyongyang's deepening cooperation with Moscow.