The time is not right for a planned trip to the Democratic People's Republic of Korea (DPRK) by Google's executive chairman, Eric Schmidt, and New Mexico's former governor, Bill Richardson, the US State Department said on Thursday.

Department spokeswoman Victoria Nuland also insisted that the duo will make the visit as private citizens and carry no messages from the government.

"Frankly, we don't think the timing of this is particularly helpful, but they are private citizens, and they are making their own decisions," Nuland said at a regular news briefing.

"As you know, they are private citizens," she added. "They are traveling in an unofficial capacity. They are not going to be accompanied by any US officials. They are not carrying any messages from us."

The trip, expected to happen as early as this month, comes at a time when the UN Security Council is still deliberating on further moves against the DPRK over its launch of a satellite last month.

Washington and its allies see Pyongyang's satellite launches as disguised ballistic missile tests banned under UN resolutions adopted following the country's nuclear tests in 2006 and 2009.