Shortly before the all-clear was expected to be given for river traffic to resume on Germany's Rhine river following dangerous flood water levels, a ship collided with a rail bridge in the city of Cologne.

The ship hit the city's South Bridge, which carries freight trains across the Rhine, at 4 a.m. (0300 GMT) Wednesday morning, the river traffic police reported.

German rail company Deutsche Bahn said that train traffic was suspended across the bridge for approximately two hours after the incident. It restarted at 6:40 a.m.

An expert examined the bridge and found no structural damage, after which trains were allowed to run again.

As the bridge carries only freight traffic, passengers were not affected, Deutsche Bahn said.

River traffic, which has been suspended for days after floodwaters took the Rhine to dangerous levels, was not affected by the accident.

Shortly before the accident, the river dropped just below the danger level of 8.3 meters, meaning that the river at Cologne could be opened up to river traffic again.

Nobody was injured in the accident, the cause of which was not initially clear.