North Korea has called on “all Koreans at home and abroad” to “promote contact (and) cooperation between North and South Korea”.
State media in North Korea also said Pyongyang would “smash” all challenges against reunification of the Korean peninsula.
Koreans are being urged to make a “breakthrough” for unification without other countries’ help.
The North’s official news agency said military tension on the Korean peninsula was a “fundamental obstacle” to the improvement of inter-Korean relations.
It added that joint military drills with “outside forces” were unhelpful when better relations between North and South Korea were being sought.
It came as the North’s ice hockey team – dressed in DPRK jackets – crossed the militarised border to form Korea’s first-ever unified team for next month’s Winter Olympics.
North and South Korea will march under one flag as the joint team competes in Pyeongchang.
The Unification Flag, which features the entire peninsula and surrounding islands in blue on a white background, was last used in 2006 at the Winter Olympics in Italy.
North Korea is sending 22 athletes to the winter games.
Twelve of those are the ice hockey players who on Thursday arrived in the South with their coach, two support staff and other officials.
They were met by several dozen protesters who shouted slogans and held a sign demanding the beheading of North Korea leader Kim Jong Un.
The players will travel to a training centre to meet their 23 South Korean teammates and were expected to start practising together later on Thursday.
A poll in the South showed around 70% were opposed to the joint hockey team, claiming it will deprive their players of time on the rink.
Tensions remain high in the region over North Korea’s series of rocket launches.
US President Donald Trump has warned the secretive state not to mess with America, and has declared the country a designated state sponsor of terrorism.