"The sides positively assessed the progress of the six-party talks on the Korean peninsula's nuclear problem and urge all involved parties to continue dialogue, negotiations and set a course to find a peaceful solution to the problem," the document said.
The declaration was issued after a meeting between Russian President Dmitry Medvedev and Chinese President Hu Jintao in Beijing, where the Russian leader arrived on Friday for his first official visit since he was inaugurated president on May 7.
The six-party talks that started in 2003 involve the two Koreas, China, Russia, the United States and Japan.
The declaration also said that Moscow and Beijing intend to continue playing an active role in finding a settlement to the issue.
Six-party negotiations stalled after Pyongyang failed last December to reveal all the details of its nuclear program, in particular information on uranium enrichment and nuclear technology, which it is suspected of passing to other countries.
Pyongyang started disabling its Yongbyon nuclear plant late last year as part of a deal with the U.S., China, Russia, Japan and South Korea in exchange for economic aid and diplomatic incentives.
According to South Korean news agency Yonhap, South Korea may purchase nuclear fuel rods stored at North Korea's main atomic facility, an issue planned to be discussed during a new round of talks.
Besides the North Korean nuclear program the leaders of Russia and China also mentioned in the joint declaration issues concerning Iran's controversial nuclear program, restoring war-torn Iraq, the Middle East situation and Kosovo's independence.
The declaration stated that all the issues should be resolved by means of political dialogue taking into account global security needs.