Media playback is unsupported on your device Media caption The BBC's Steve Evans says that police think other arsonists are still at large

A man has reportedly admitted burning more than 100 luxury cars in the German capital Berlin, in attacks that raised fears of political extremism.

Police say the 27-year-old, who is unemployed and has debts, was motivated by social envy and frustration to set fire to 67 cars over three months.

A further 35 cars parked nearby also went up in flames.

Some 470 cars - mainly BMWs, Mercedes and Audis - have been burnt this year in the city.

Such was the extent of the problem this year, up to 500 police were deployed on the streets at night to look for suspects and a 150-member dedicated squad was set up.

Berlin police also asked the federal authorities for high-tech equipment and helicopters with thermal image cameras.

The suspect was arrested on Sunday and confessed he had torched 67 cars between June and August, admitting that on several occasions the fire had spread to neighbouring cars.

"He wasn't motivated by politics but rather social envy," said senior police official Oliver Stepien. "He said in essence: 'I've got debts, my life stinks and others with fancy cars are better off and they deserve this'."

Earlier this month, the Berlin railway system was hit by arson attacks. Explosive devices were placed in a number of locations, including at least one on a high-speed rail track.

A previously unknown left-wing group, calling itself the Hekla Reception Committee, said it had planted the devices.