翻译原文：

German official reports ‘massive assaults’ on police as thousands gather ROSTOCK, Germany - Masked demonstrators showered police with rocks and beer bottles, then were driven back with water cannons and tear gas during a protest march Saturday against the upcoming Group of Eight summit in Germany.

The clashes left smoke from burning cars and the sting of tear gas drifting through the harborfront area in the north German port of Rostock. Some 146 police were hurt, 18 of them seriously. There were no immediate figures on the number of protesters injured.

The officially permitted march preceded a three-day summit beginning Wednesday in the seaside resort of Heiligendamm, where German Chancellor Angela Merkel hosts the leaders of the other G-8 nations—Britain, France, Japan, Italy, Russia, Canada and the United States.