Terming the development of inter-Korean relations as 'unrealistic', North Korea on Tuesday said that engaging in cross-border ties with South Korea is not possible as the latter has given in to US pressure, the local media reported.

Last month the unification ministry of South Korea had come up with its plan to move bilateral relations with North Korea forward. The plan included North Korean leader Kim Jong-un's visits to Seoul and holding of inter-Korean summits, Yonhap news agency had reported.