China said on Tuesday it was open to a visit by new North Korean leader Kim Jong-un following the death of his father Kim Jong-il, as President Hu Jintao visited the hermit state's embassy in Beijing to express his condolences.

Chinese Foreign Ministry spokesman Liu Weimin, speaking at a daily news briefing, initially said he had no information about whether Jong-un would be welcome to visit China.

But later he clarified: I want to add that China and North Korea have always kept up high-level visits, and we welcome the North Korean leader to visit at a convenient time to both sides. He did not elaborate.

The remarks follow a message from China's central leadership on Monday that gave Beijing's support for isolated North Korea and expressed confidence in Kim Jong-un -- Kim Jong-il's young and little-known successor.

Hu, during his visit to North Korea's sprawling embassy in one of Beijing's leafy diplomatic quarters, offered his support for the country's new leader, Kim Jong-un, highlighting efforts to shore up friendship with Pyongyang under the younger Kim.

State television showed a grim-faced Hu bowing in mourning for the elder Kim, accompanied with several other top officials, including Vice President Xi Jinping, the man most likely to succeed Hu from late next year.

We are confident that the people of North Korea will carry on the task bequeathed by Comrade Kim Jong-il, and closely unify around the Korean Workers' Party, and under Comrade Kim Jong-Un turn their anguish into strength, Hu said in his condolence remarks.

Cooperative relations between China and North Korea is the immutable and unwavering guiding policy of China's party and government, the report paraphrased Hu as saying.

The visit -- unusual for China's highest ranked leader -- is another sign of Beijing's determination to protect its ties with Pyongyang as it enters an uncertain transition.

Chinese Foreign Minister Yang Jiechi had spoken in the morning with his South Korean counterpart Kim Sung-hwan and U.S. Secretary of State Hillary Clinton.

All three agreed it was important to maintain peace and stability on the Korean peninsula, the statement, carried on the ministry's website (www.mfa.gov.cn), said.

Maintaining peace and stability on the Korean peninsula accords with the interests of all sides. China is willing to work hard with all sides to this effect, it cited Yang as saying.

Impoverished and squeezed by international sanctions for conducting a series of nuclear and missile tests since 2006, North Korea has increasingly turned to Beijing for help to fill the gap left by the drying up of economic assistance from South Korea and the United States.

In turn, China has made clear that it wants to shore up North Korea as a buffer protecting its regional influence from the United States and its allies.

Over the 18 months before his death, Kim visited China four times, although in the past he rarely travelled abroad.

During Kim's China visit in May, the two sides vowed that their alliance, sealed in blood, would pass on to their successors.

(Writing by Ben Blanchard)