Regional powers have managed to produce "significant progress" in their drawn-out talks on how to punish North Korea for its latest rocket launch, multiple diplomatic sources said Thursday.

But nobody can pin down the exact timing of a deal, a source in Washington said.

"It's true that there has been significant progress in the discussions at the U.N. Security Council," one source told Yonhap News Agency. "Members of the council are working to finalize the consultations. There is a common perception that the U.N. response should be hammered out first to move on to a next phase in efforts to bring North Korea to dialogue."

North Korea fired a long-range rocket in mid-December in violation of U.N. resolutions that ban it from using ballistic missile technology.

The U.S., South Korea and their allies have been pressing for tough U.N. measures in the form of either a fresh resolution or another statement by the council's chairman.

China, a communist ally of North Korea and a veto-wielding member of the U.N. council, has been apparently uncooperative.

"It seems like China is relatively more active than before," the source said on the condition of anonymity.

An informed source in Moscow also told Yonhap that the council is expected to announce a measure against North Korea as early as this weekend.

The source said a chairman's statement is more likely than a new resolution.

Still, the Washington source said it's too early to rule out the possibility of a resolution.

"Given the characteristics of multilateral discussions in the U.N., it's difficult to confidently say about the timing and format of such a measure," the source said.

In Seoul, meanwhile, U.S. and South Korean officials said they expect an agreement in the near future.

 "We're actively engaged in diplomacy and we recognize how important the outcome is and we anticipate formal steps in the Security Council in the immediate future," Assistant Secretary of State Kurt Campbell told reporters during his trip there.

Cho Tai-young, spokesman for South Korea's foreign ministry, also said Seoul expects a measure sooner or later.

South Korea, which began its two-year term as a nonpermanent member of the council this month, is working to "make its utmost possible achievement," he added. (Yonhap News)