South Korea's president sought to galvanize support from world leaders to pursue UN Security Council punishment for North Korea if it proceeds with a rocket launch that is suspected to be a cover for a missile test. President Barack Obama is expected to join the push for a joint response to the launch when he meets with South Korea's Lee Myung-bak on Thursday. But it will be harder to convince President Hu Jintao of China, the North's only major ally, on Friday. As world leaders prepared a response to the launch, CNN television reported that the North's own preparations were continuing. The US network said on its Web site that Pyongyang has begun fueling the rocket, citing an unidentified senior US military official. South Korea's Defense Ministry said it was aware of the report but declined to comment. In one-on-one meetings Wednesday in London ahead of the G-20 summit, Lee stressed the need for a "united response" among world leaders after Pyongyang carries out what it has said will be a satellite launch some time from Saturday to Wednesday.