Seoul: The United States said yesterday it was open to negotiations with North Korea over its nuclear ambitions as attention focused on whether China had managed to persuade the North to defuse the mounting crisis.

Chinese President Hu Jintao sent a high-level envoy to Pyongyang for talks with North Korean leader Kim Jong-il amid growing speculation that Pyongyang might be about to detonate a second nuclear device.

"We want to leave open the path of negotiations. We don't want the crisis to escalate," US Secretary of State Condoleezza Rice told a news conference with South Korean Foreign Minister Ban Ki-moon in Seoul.

"I hope it [China] has been successful in saying to North Korea that there is really only one path, which is denuclearisation and dismantlement of its programmes."

China, the communist state's strongest backer, announced earlier that Tang Jiaxuan, a state councillor and former foreign minister, had delivered a message from Hu to the North's Kim.

China's foreign ministry gave no details of the message but said the visit was of "major significance".

Rice is expected to meet Tang when she goes to Beijing today on the third leg of her trip to East Asia that began in Tokyo on Wednesday.

North Korea's state news agency KCNA, in an unusually quick report on any meeting with Kim, said the talks with the Chinese envoy had been conducted in a "friendly atmosphere".