MOSCOW — North Korean leader Kim Jong Il says his country is ready to impose a nuclear test and production moratorium if international talks on its atomic program resume, in Pyongyang’s latest effort to restart long-stalled, aid-for-disarmament talks.

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.”

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.

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.

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.

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.