The detection of a World War II era bomb in the southern German town of Rastatt on the Karlsruhe-Basel route has disrupted services to the Swiss city of Basel.

The line is a significant north-south junction for passengers transiting to and from Germany from the Alpine nation.

The bomb was discovered 30 to 40 centimeters (1 to 1.5 feet) from the tracks. The bomb itself is 70 to 80 centimeters and weighs 250 kilograms.

Deutsche Bahn tweeted there are "cancellations between Karlsruhe and Basel and diversions between Stuttgart and Paris." 

Users of the Deutsche Bahn app were alerted to the "disposal of unexploded ordinance," with several trains cancelled all together and affected passengers being rerouted.

Baden-Württemberg police tweeted, "The railway line is currently closed in this area." 

Explosive ordinance disposal experts are on site, Deutschlandfunk reports.

The district of Niederbühl, in southern Rastatt, is to be evacuated at a radius of 500 meters but could be increased to one kilometer if necessary. Five thousand people are affected by the evacuations.

It is not known how many people will have to be evacuated nor how long the closure will last.

ar/jcg (dpa)