Up to 76 people were rescued from cable cars suspended over the river Rhine in Cologne on Sunday afternoon after a gondola crashed into a support pillar, leaving passengers stranded.

German fire crews lowered people to safety from cable cars in a dramatic recovery operation, with children seen clinging to parents as they dangled 40 metres above the river.

German media reported that rescue teams in Cologne had practised for an incident on the gondola just a week ago.

A pregnant woman and a man were slightly injured in the rescue mission in which mobile cranes were used to bring the stranded passengers to safety. No other injuries were reported.

Public transportation authorities for the city in North-Rhine-Westphalia state said 32 gondolas were operating when the incident occurred. An official cause has not been announced, but there was strong wind at the time.

Martina and Hans-Peter Rieger, the first to be rescued, were celebrating their 41st wedding anniversary on a day out in Cologne when the cable cars stopped. “That will always be in our memory,” Mr Rieger said. “Fortunately, we were given hand signals to tell us we should remain calm and the incident was nothing bad.”

Emergency services from Aachen and Dusseldorf assisted fire crews with the rescue.

Passengers are evacuated after the cable car accident in Cologne. Photograph: Sascha Steinbach/EPA

Henriette Reker, the mayor of Cologne, said: “I would like to thank the Cologne fire brigade for their great dedication. This meant that the passengers could be rescued quickly. My thoughts were with the children and adults, who had to wait courageously and patiently for many hours.“

The cable cars in Cologne are a popular means of transport, connecting the zoo to the Rheinpark across the river. The system remained close on Sunday evening as officials worked to establish the cause.