The key to solving the issue of Pyongyang's ballistic missile and nuclear programs is in the United States' hands, China's UN envoy Zhang Jun said on Friday, urging Washington to show "more sincerity and flexibility" if it wants a breakthrough.

He spoke ahead of a closed UN Security Council meeting, which was requested by the United States to discuss the Democratic People's Republic of Korea's launch of an intermediate-range ballistic missile last Sunday.

Zhang told reporters that China understands the U.S. wants to solve the problems on the Korean Peninsula, but if the U.S. wants to see breakthroughs, "they should show more sincerity and flexibility."

"The key to this issue is already in the hands of the United States," the ambassador said.

Zhang said the U.S. is a direct party to the Korean Peninsula issue and that "the solution lies in dialogue." 

After the meeting, U.S. Ambassador to the United Nations Linda Thomas-Greenfield told reporters that Washington has to "keep up the pressure."

The U.S. along with seven other council members – Albania, Brazil, France, Ireland, Norway, the United Arab Emirates and Britain – issued a joint statement condemning Pyongyang's launch (January 30) as a "significant escalation" that "seeks to further destabilize the region."

Zhang said the council should only issue a statement if it is "helpful for the deescalation of the tensions." Such statements by the council have to be agreed by consensus.

(With input from agencies)