Arson attacks on cars in the German capital Berlin have escalated with over 60 set on fire in the past week.
Mindful of the recent riots in England, Chancellor Angela Merkell says the attacks fill her with great concern.
''What kind of behaviour is this?'' she asked. ''People's lives are being put at risk in cold blood.''
But Mayor Klaus Wowereit said the burnings have "nothing to do with" the British riots.
He said the attacks were once politically motivated.
''But the latest incidents are different. The fires are being lit across the area,'' he said.
More than 130 cars have been set on fire this year, similar to the annual totals since the phenomenon appeared in 2007. But Berlin police are at a loss to profile the arsonists or explain their motives.
Social Democrat MP Dieter Wiefelspuetz called the attacks ''a precursor to terrorism''.
He recalled that the far-left Red Army Faction active in the 1970s and 1980s began with arson and before resorting to bombings and assassinations.
RAF founder Ulrike Meinhof once said: ''If one sets a car on fire, that is a criminal offence. If one sets hundreds of cars on fire, that is political action.''
Only one person has been convicted so far.