SEOUL, April 1 (Reuters) - North Korea's Kim Yo Jong, the powerful sister of leader Kim Jong Un, accused Ukraine of calling for nuclear weapons, state media KCNA reported on Saturday, basing her assertion on an online petition in that country that has drawn under 1,000 signatures so far. Following Russian President Vladimir Putin's announcement last week that Moscow plans to station tactical nuclear weapons in Belarus, a public petition was filed to the Ukrainian presidential office's website on Thursday, calling for Ukraine to host nuclear weapons on Ukrainian territory, or for it to be armed with its own nuclear weapons. See here for a complete list of exchanges and delays