World leaders are welcoming North Korea's declaration of its nuclear program, but say they remain cautious until they can verify the North Korean claims.

Speaking at the Group of Eight foreign ministers' meeting in Tokyo, Japanese Foreign Minister Masahiko Komura Thursday said North Korea's declaration is only one step in the process of ending the country's nuclear weapon program.

In 2006, Tokyo closed its ports to North Korean-registered vessels and banned most trade with its neighbor in response to Pyongyang's missile and nuclear tests.

Japan also demands that North Korea fully account for Japanese citizens who the North abducted in the 1970s and 1980s.

Meanwhile, the Interfax news agency today quoted Russian Deputy Foreign Minister Alexei Borodavkin as saying the next round of six-party talks on disarming North Korea's nuclear weapons could be held next week.

Talks between China, Japan, Russia, the United States and North and South Korea began in 2003 and had been stalled, awaiting Pyongyang's release of its nuclear declaration.

Some information for this report was provided by AFP, AP and Reuters.