SEOUL (TIP): North Korea will gain “nothing” by making threats, US President Barack Obama said on Friday, warning it of sanctions with “more bite” if it went ahead with a fourth nuclear test. Speaking in South Korea as satellite images revealed the North could be preparing for another test, Obama stressed that Washington and Seoul stood “shoulder to shoulder” in their refusal to accept a nuclear North Korea.

Even China, the North’s only major ally, was becoming alienated by its provocative behaviour, he said on the second leg of his Asian tour. “Threats will get North Korea nothing, other than greater isolation,” Obama said at a joint press conference with South Korean President Park Geun-Hye.

“China is beginning to recognise that North Korea is not just a nuisance but a significant problem for their own security,” he added. North Korea-watchers have puzzled over whether the test preparations at the Punggyeri test site they have seen via satellite images are real, or bravado aimed at stealing the limelight during the US president’s tour.