North Korea has backtracked on an inter-Korean agreement to allow South Koreans to travel to and from the Gaesong Industrial Complex between 7 a.m. and 10 p.m.

The Unification Ministry said Thursday that the North cited what it called 'operational difficulties' in extending the travel time for South Korean visitors.

At their prime ministers' talks last year, South and North Korea agreed to allow South Koreans to travel to the South-North joint industrial park on the cross-border Gyeongui highway from 7 a.m. to 10 p.m. beginning mid-January.

But the extension of the travel time was postponed until Thursday at the North's request.

South Koreans are currently banned from traveling on the road between 8 a.m. and 5 p.m.

North Korea earlier demanded South Korea supply power for street lamps along the highway and construction materials.