North Korea (search) on Sunday confirmed that it had met with U.S. officials this month, implying that its return to six-party talks on its nuclear program depended on "the U.S. side's attitude."

U.S. officials said last week the two sides had met on May 13 in New York, characterizing the discussions as "working-level contacts."

The cryptic statement from the North Korean Foreign Ministry said Pyongyang would continue to "closely watch the U.S. side's attitude and will deliver its position when the time comes."

The statement was carried by North Korea's official Korean Central News Agency.

The meeting, reportedly at the North Korean representative office at the United Nations, came as concerns are mounting that the reclusive regime is moving toward extracting weapons-grade plutonium and could be preparing for a nuclear test.

The United States, China, South Korea, Japan and Russia are trying to persuade North Korea to return to six-nation talks on its nuclear weapons programs. The talks have been stalled since June.