Condoleezza Rice, the US secretary of state, has called on North Korea to return unconditionally to six-party talks on ending its nuclear programme.
"The DPRK should return to these talks without conditions," Rice said following a meeting with Li Zhaoxing, the Chinese foreign minister, in Beijing on Friday.
The call came amid media reports that Kim Jong II, the North Korean leader, has expressed regret about his country's nuclear test and willingness to return to disarmament talks if the US eases its pressure.
Chosun Ilbo, the South Korean newspaper, quoting an unidentified diplomatic source in China, said Kim made the remarks to a high-level Chinese delegation visiting Pyongyang this week.
"Chairman Kim conveyed his sorry feelings about the nuclear test," the paper quoted the source as saying.
"If the United States makes concessions to some degree, so will we, be it either at the bilateral level or the six-party talks," Kim was quoted as saying when he met the delegation led by Tang Jiaxuan, the Chinese state councillor, on Thursday.
China said Tang, President Hu Jintao's special envoy, had delivered an important message from Hu to Kim during a "significant" mission.
It was the first time Kim is known to have met any foreigner since the October 9 nuclear test, which sparked international uproar and sanctions against the impoverished communist state.
"Fortunately my visit this time has not been in vain"
Tang Jiaxuan, Chinese special envoy to Pyongyang
Tang meanwhile told Rice on Friday that his talks with Kim had achieved some positive results.
"Fortunately my visit this time has not been in vain," Tang told the visiting US secretary of state.
The Chinese foreign minister also reported progress from the encounter, saying the prospect of quickly resuming the stalled six-party talks on Pyongyang's nuclear programme had been discussed.
"At least it increased mutual understanding," Li told reporters when asked about the meeting. "Everyone discussed how to restart progress in the six-party talks as quickly as possible."
The United States and other nations have been pushing China, the North's only remaining major ally, to use its influence to curtail Kim's nuclear ambitions.
According to a South Korean official, the North gave China only about 20 minutes' advance notice of the test.
Beijing - which had invested much diplomatic capital hosting six-nation disarmament talks involving the two Koreas, China, Japan, Russia and the United States - reacted angrily and denounced the test as "brazen".
North Korea agreed at the six-nation forum in September 2005 to scrap its nuclear programmes in exchange for energy aid and security benefits.
But it boycotted the forum two months later in protest at US attempts to curb its access to overseas banks.