Johannesburg, Apr 26 : Dismissing North Korea's nuclear threats, US President Barack Obama has reportedly warned the country of tougher sanctions if it were to go ahead with its fourth nuclear test.

Obama said at a joint press conference with South Korean President Park Geun-Hye that threats will get North Korea nothing, other than greater isolation.

According to News24, 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.

Obama also said that China is beginning to recognise that North Korea is not just a nuisance but a significant problem for their own security.

When asked how the international community might react to North Korea's fourth nuclear test, Obama reiterated that it would be necessary to look at additional ways to apply pressure, including further sanctions that have even more bite. (ANI)