* New Chinese leader says wants to promote reconciliation
* U.S. hopes Russia and China will discuss sanctions
* Security Council strengthened sanctions after nuclear test (Adds remarks by U.S. official in Russia)
By Sui-Lee Wee and Gabriela Baczynska
BEIJING/MOSCOW, March 20 (Reuters) - China is willing to promote dialogue between North and South Korea as stability on the Korean peninsula is also in China's interests, President Xi Jinping told his South Korean counterpart on Wednesday, China's Foreign Ministry said.
A U.S. official said Washington hopes that Xi, who is to visit Moscow this week on his first trip abroad as president, will discuss implementation of sanctions on North Korea with Russian President Vladimir Putin.
Beijing is Pyongyang's sole diplomatic and economic ally, but relations have been strained by North Korea's bellicose actions, including carrying out a third nuclear test last month.
"Peace and stability on the Korean peninsula is in the vital interests of the people of the peninsula and also of the Chinese people," Xi told President Park Geun-hye in a telephone call, the Foreign Ministry said in a statement.
"China is committed to maintaining peace and stability on the peninsula and realising the peninsula's denuclearisation, and upholds resolving the issue through dialogue and consultation," Xi added.
"China is willing to provide necessary help to promote reconciliation and cooperation."
Beijing supported a new round of sanctions that were unanimously approved by the U.N. Security Council this month and has said it wanted them implemented.
But questions remain over how closely it imposes restraints on its neighbour, viewed as both an embarrassment and a strategic bulwark against U.S. influence in the region.
Speaking in Moscow on Wednesday, a U.S. State Department official said Washington expected talks conducted during Xi's visit to Russia would touch on North Korea.
"Our hope would be that they would talk about how to best implement the decisions made at the level of the Security Council in order to try to change North Korea's thinking and its direction to a more useful, productive, peaceful path."
The official said there should be "a greater degree of solidarity diplomatically among the countries most directly engaged with North Korea."
"Rather than allowing the North Koreans, as happened too often in the past, to be able to kind of split us by appealing to the nuances and differences in our set of interests on North Korea," the official added.
While experts say North Korea is years away from being able to hit the continental United States with a nuclear weapon, its fiery rhetoric and aggressive testing have increased tensions with the United States and its allies South Korea and Japan.
China and Russia, permanent U.N. Security Council members with veto power, have backed U.N. sanctions including measures approved on March 7 to impose financial restrictions and crack down on Pyongyang's attempts to ship and receive banned cargo.
But Moscow has also often balanced criticism of Soviet-era client state North Korea's nuclear tests and missile launches with calls on other powers to refrain from belligerent actions against Pyongyang saying they are counterproductive.
Both China and Russia criticised U.S. plans to strengthen an anti-missile shield by deploying more interceptors in Alaska after North Korea threatened a preemptive nuclear strike against the United States. (Reporting by Ben Blanchard, Huang Yan, Sui-Lee Wee, and Gabriela Baczynska; Editing by Dean Yates and Steve Gutterman)