Seoul: North Korea on Thursday toughened its stance on neighbouring South Korea and said that dialogue between the two countries is not open and Pyongyang is in direct talks with Washington without mediation, denying Seouls statements on the matter. Director-General of Department of American Affairs of North Korean Foreign Ministry, Kwon Jong-gun, said that Seoul was “trying to refurbish their image by giving a publicity as if they are ‘mediating’ the North Korea-US relations”, according to a statement released by state news agency KCNA. (IANS)