There would be "more developments in the days ahead" in Washington's push to punish North Korea for its rocket launch, said a top US diplomat  Wednesday.

Kurt Campbell, assistant secretary of state for East Asia, told reporters in Seoul that the US was in talks with the key players at the UN, including China and Russia, over potential sanctions against Pyongyang, Xinhua reported.

"We're very clear in our position that provocative steps are to be discouraged," Campbell, who arrived in Seoul a day ago on a two-day visit, told reporters.  "We are closely working with the key players including South Korea at the UN with respect to our diplomacy after the missile test late last year."

North Korea launched a satellite last month despite being banned by UN resolutions from conducting any ballistic missile tests.

Pyongyang said the launch was for scientific and peaceful purposes only.

Campbell, who is scheduled to meet with South Korea's President-elect Park Geun-hye later in the day, said policy coordination between the two countries would continue under the new leadership in Seoul. 

The US diplomat, who leaves for Japan later Wednesday, is accompanied by Assistant Secretary of Defense Mark Lipper and National Security Council Senior Director for Asian Affairs Daniel Russel.