Police said they had detained around 300 people. A medical tent dealt with 93 injuries, from baton bruises to dog bites.

By first light on a misty morning, the containers had sneaked out of the railhead at Dannenberg. The shipment moved at a snail's pace along the 20 km (12 miles) road to the storage site at Gorleben, the final stop of a 1,500 km (930 mile) trip back from a reprocessing plant in northwestern France.

The containers had arrived in Dannenberg by rail late this week as helicopters circled overhead, police sirens wailed and protesters, held 500 metres (1,600 ft) from the track, blew whistles.

Dannenberg was packed with police vans, armoured personnel carriers and water cannon vehicles.

Previous shipments have been hit by violence and disruption from Germany's anti-nuclear lobby. Police and protesters said fewer people than expected had joined the latest demonstration.

"Look at the way the police have limited people's movement, although I don't blame them. I think many of them would rather be on our side," said protester Detlet Puls, 51.

The shipments to the Gorleben storage site have become a ritual confrontation between police and anti-nuclear activists. They resumed in March after a break of three years. The policing bill to protect the last shipment in March was around 50 million marks ($22.5 million).

"You can imagine it won't be any less this time," said a police spokesman.

Nuclear power is a controversial issue in Germany, where government and industry agreed last year to gradually phase out all reactors by around 2025.