North Korea's top nuclear envoy arrived in Beijing on Tuesday after two days of unofficial talks in Singapore with former U.S. diplomats on his country's nuclear and missile programs.

Ri Yong-ho, the North's chief negotiator to the long-stalled six-party talks on Pyongyang's nuclear weapons program, was tightlipped on whether he plans to meet with his Chinese counterpart Wu Dawei in Beijing.

Upon his arrival at the Beijing airport, Ri was whisked into a waiting sedan with a North Korean embassy plate.

In Singapore, Ri made no new proposal on the nuclear issue, repeating only that North Korea would temporarily suspend nuclear tests if the United States halts joint military exercises with South Korea scheduled for this year. Both Seoul and Washington had rejected the proposal.

A former U.S. special envoy for North Korea policy, Stephen Bosworth, was among Ri's  dialogue partners in Singapore on Sunday and Monday. The others included former deputy U.S. nuclear negotiator Joseph DeTrani and Leon Sigal, director of the Northeast Asia Cooperative Security Project at the Social Science Research Council.

Although the U.S. government was not involved, former American officials and North Korean diplomats have occasionally held unofficial talks to help the two governments  better understand each other's position.

The six-party denuclearization talks have been suspended since late 2008.

In Beijing on Tuesday, China's foreign ministry spokeswoman Hua Chunying welcomed the unofficial dialogue in Singapore between Ri and the former U.S. officials, saying China expects the relevant countries to create conditions to resume the six-nation talks.

Relations between the U.S. and the North have worsened further recently following a cyber-attack on entertainment company Sony Pictures. The U.S. has blamed the North for carrying out the attack and imposed fresh sanctions, but Pyongyang has categorically denied its involvement. (Yonhap)