For the first time in 12 years athletes from North and South Korea will march under separate flags during tonight’s Olympic Games opening ceremony in Beijing.

The president of the International Olympic Committee, Jacques Rogge, said the two countries had originally agreed to put their political differences aside and march together under one blue and white “unification flag”.

However Mr Rogge said the deal was cancelled by political leaders in Pyongyang and Seoul and despite being “a setback for peace, and harmony and reunification”, the IOC must accept the decisions of sovereign governments.

“There was a great willingness on the side of sport to have a joint march like we did in Sydney and in Athens,” Mr Rogge said. “Unfortunately, both the political powers in the South and the North did not agree, and I regret this very much.”

The two countries, which have never signed a peace treaty to officially end the 1950-1953 Korean War, started the joint marches as part of a thaw in relations in 2000.

They marched together in the athletes’ parade during the opening ceremony at the Sydney Games in 2000 and again in Athens in 2004. However they will now march separately for the first time since the Atlanta Olympics in 1996.

Three years ago both North and South Korea announced a plan to participate as a single team at the Beijing Games. But talks were reportedly halted over disagreements on the composition of the team and increased tensions between the two countries in recent months.