It remains to be seen, however, whether Kim's reported gesture at a summit Wednesday with Russian President Dmitry Medvedev will satisfy the most skeptical of the five other nations at talks meant to end the North's nuclear weapons ambitions -- the United States, South Korea and Japan.
U.S. State Department spokeswoman Victoria Nuland said Wednesday that Kim Jong Il's reported offer to refrain from nuclear and missile tests was "a welcome first step" but not enough to restart six-party disarmament talks.
Kim, at the summit in eastern Siberia, reportedly made no mention of an issue that lies at the heart of negotiators' worries: North Korea's recently revealed uranium enrichment program.
Medvedev spokeswoman Natalya Timakova was quoted by the ITAR-Tass news agency as saying that Kim expressed readiness to return to the nuclear talks without preconditions, and, "in the course of the talks, North Korea will be ready to resolve the question of imposing a moratorium on tests and production of nuclear missile weapons."
Nuland said North Korea's disclosure of a uranium enrichment facility last November "remains a matter of serious concern" that violates U.N. resolutions and commitments Pyongyang had made on denuclearization in 2005.
"We will not go back to six-party talks until North Koreans are prepared to meet all of the commitments that we've all laid out," Nuland told a news conference in Washington.
The North promised to freeze its long-range missile tests in 1999, but has since routinely tested short-range missiles and launched a long-range rocket in April 2009. It has also conducted two nuclear tests, most recently in 2009, and last year it shelled a South Korean front-line island, killing four, and allegedly torpedoed a South Korean warship, killing 46.
Kim and Medvedev met at the hotel of a military garrison near the city of Ulan-Ude in Buryatia, a predominantly Buddhist province near Lake Baikal. It is Kim's first trip to Russia since 2002, and it follows a marked easing in tensions between North and South Korea.
Nuclear envoys from the Koreas met last month on the sidelines of a regional security summit for what were described as cordial talks. A senior North Korean official then traveled to New York for talks with his U.S. counterparts.
The North has repeatedly said it wants the so-called six-party nuclear talks to resume. Washington and Seoul, however, have been wary, calling first for an improvement in the abysmal ties between the Koreas and for a sincere sign from the North that it will abide by past commitments it has made in previous rounds of the nuclear talks.
South Korea's Yonhap News Agency said in an editorial that many had hoped the summit would signal change for the tense Korean peninsula, but the results instead seemed a "'storm in a teacup,' lacking any new content."
"The communist country has a track record of alternately using provocations and dialogue with South Korea, the United States and other regional powers to try to wrest concessions before backtracking on agreements and quitting the nuclear talks," the editorial said of the North.
Yonhap quoted an unnamed South Korean official as saying the results fell short of the expectations of South Korea, the United States and Japan. The official raised the need for the North to address its uranium enrichment program.
The six-sided nuclear talks involving North Korea and the United States, China, Japan, Russia and South Korea have been stalled since December 2008. But faced with deepening sanctions and economic trouble, North Korea has pushed to restart them.
Yang Moo-jin, a professor at the University of North Korean Studies in Seoul, hailed the North's willingness to freeze its missile and nuclear tests, but noted there was no clear mention of the North's uranium enrichment program, which can also make nuclear weapons.
"The North already has weaponized plutonium, and enriched uranium is something that can be proliferated in an easier manner," Yang said.
On another subject, Medvedev said Russia and North Korea moved forward on a proposal to ship natural gas to South Korea through a pipeline across North Korea.
North Korea had long been reluctant to help its powerful archenemy increase its gas supply, but recently has shown interest in the project. The South wants Russian energy but is wary of North Korean influence over its energy supply.
Medvedev, in televised comments, said the two countries will create a commission on "bilateral cooperation on gas transit."
He said two-thirds of the 700-mile (1,100-kilometer) pipeline would traverse North Korea to stream up to 10 billion cubic meters of gas a year to the South. Russia's state-controlled gas monopoly, Gazprom, said the pipeline is likely to carry gas from the giant offshore fields near the Pacific island of Sakhalin.
The two leaders also discussed restructuring North Korea's Soviet-era debt to Russia, said a Kremlin official, speaking on condition of anonymity. That debt totals about $11 billion, according to a top Russian official.
The North's launching of a long-range rocket in April 2009 drew widespread international sanctions and condemnation, and an angry North Korea retaliated by pulling out of the six-party nuclear talks.
North Korea is believed to have enough weaponized plutonium for at least six atomic bombs and last November it revealed a uranium enrichment program. North Korea has carried out two nuclear tests, in 2006 and 2009, and is believed to be working toward mounting a bomb on a long-range missile.
In March, Russian Deputy Foreign Minister Alexei Borodavkin traveled to Pyongyang and urged North Korean officials to impose a moratorium on nuclear and ballistic missile tests and to allow international monitors back into its main nuclear complex near the capital.
Kim was expected to return to North Korea following his meeting with Medvedev.
The itinerary for Kim's visit has been largely kept secret due to security worries. Some photos of Kim emerged during his visit Sunday to a Russian hydroelectric plant -- whose power lines might be extended to North Korea -- but heavy police cordons have kept the media and onlookers in Ulan-Ude away from the train station.
Kim also reportedly visited a major aircraft factory that produces the Sukhoi attack planes and the town of Skovorodino, the starting point for an oil pipeline that links eastern Siberian oil fields to China.
At their summit, Medvedev greeted Kim, who stepped out of an armored Mercedes limousine saying he was "having a fun trip." Kim, however, looked frail as he limped to a chair in a meeting hall -- a possible consequence of a stroke he reportedly had in 2008.
Klug reported from Seoul. Hyung-jin Kim and Sam Kim in Seoul, Jim Heintz in Moscow and Matthew Pennington in Washington contributed to this report.