Facing a US-led push for tough United Nations sanctions over its latest nuclear test, North Korea sent on Friday top diplomats to Moscow and possibly Beijing.

Facing a US-led push for tough United Nations sanctions over its latest nuclear test, North Korea sent on Friday top diplomats to Moscow and possibly Beijing.

China and Russia, both veto-wielding permanent members of the Security Council, have helped temper the international reaction to North Korean provocations in the past.

The North's official KCNA news agency said a delegation led by Vice Foreign Minister Pak Myong-Guk had departed for Russia on Friday.

No details were given of the itinerary, but the visit comes as Washington is seeking to build a regional and international consensus on the need for harsh sanctions after the North carried out its fourth nuclear test earlier this month.

Meanwhile, South Korea's Yonhap news agency, citing unidentified sources, said a top North Korean foreign ministry official had been spotted arriving at Beijing's international airport.

The official, Choi Son-Hui, was a former deputy head of delegation to the long-stalled six-party talks on North Korea's nuclear program, involving the two Koreas, China, Japan, Russia and the United States.

There was no information on Choi's itinerary and it was not immediately clear if she was planning to visit China or transit to a third country.