The top US diplomat for East Asian affairs warned North Korea yesterday against any "provocative" act, as concerns grow that Pyongyang might be preparing a nuclear test. "We are very clear in our position that provocative steps are to be discouraged," assistant secretary of state Kurt Campbell said in Seoul when asked about nuclear test speculation. He was in Seoul to meet with top officials, including president-elect Park Geun-hye. The impoverished but nuclear-armed North successfully staged a long-range rocket launch in December, sparking global security concerns that it was a disguised ballistic missile test. It drew UN condemnation and calls from the US and its allies for tougher sanctions. The US-Korea Institute at Johns Hopkins University, citing satellite imagery analysis, said late last month North Korea was capable of carrying out a nuclear test at two weeks' notice after repairing damage to its test facility. Campbell said "intense deliberations" were under way at the UN Security Council on how to punish Pyongyang for last month's rocket launch. "We anticipate formal steps in the Security Council in the immediate future," he said.