US ready to negotiate with North Korea: Campbell

US Assistant Secretary of State Kurt Campbell has said that US is ready to negotiate with North Korea but stressed the need to punish Pyongyang. In a meeting with North Korean high-up, Campbell said that US would dialogue with North Korea only if the later gave up nuclear program. He said that US was trying to solve this issue by consulting with South Korea. He said that sanctions on North Korea would be toughened, adding that five-party talks could also be held in this regard.