The United States has taken a step back from its warning to North Korea over a potential missile test, saying it "advised" Pyongyang to stick to its moratorium and return to dialogue.

White House spokesman Tony Snow on Friday told a daily briefing that the global community has advised, not warned, that Pyongyang refrain from test-firing a missile.

The Seoul-based Yonhap News Agency also quoted an unnamed State Department official as saying the North has yet to make a firm decision on whether to proceed with the missile test.

In 1998, North Korea shocked the world by launching a three-stage missile over Japan, saying the projectile was a satellite going in orbit. A year later, it agreed on a moratorium on further test-fires.

Snow also urged Pyongyang to return to the six-party nuclear talks.