Hamburg police say extremist left-wing opponents of a planned G8 summit in June next year in Germany were behind the arson attack this week on a car belonging to the wife of Social Democrat Deputy Finance Minister Thomas Mirow.

Mirow, 53, is responsible for policy on Europe, financial markets and currency. The vandals also threw rocks and paint at his home. Mirow was economy minister in Hamburg from 1997 to 2001 and has been deputy finance minister since 2005.

On Wednesday, Hamburg state police said a letter claiming responsibility for the attack led them to believe it was an act of protest against the G8 summit which is scheduled to take place in the Baltic Sea resort of Heiligendamm in June.

The letter was sent to the Hamburger Morgenpost newspaper. Police said it claimed Mirow's position as deputy finance minister put him "at the controls of various strategic levers of power." Authorities did not disclose further information on the letter-writers, saying they didn't want to give the group any publicity.

Shadow of Genoa?

The crime appears to be one of a growing number of violent acts attributable to militant opponents of the Group of Eight wealthiest industrial nations.

The German office for the protection of the constitution warned in early December of possible attacks from left-wing extremist groups opposed to the policies of the G8, a grouping of industrialised nations that comprises Britain, Canada, France, Germany, Italy, Japan, Russia and the United States.

The annual G8 summits are often the focus of anti-globalization movement protests. The most notable of these was at the 27th G8 summit in Genoa, in 2001, which was overshadowed by riots in the city after a crackdown by police and the death of a 23-year-old protestor.

Growing number of attacks

A spokesperson for the police group responsible for next year's summit security said this was the 37th attack so far by miltant G8 opponents. Thirteen of the 37 attacks were arson attempts.

Germany's Federal Criminal Police (BKA) has voiced concern over the rise in left-extremist violence.

"In these arson cases, the perpetrators accept the fact that it could lead to personal harm," BKA President Jörg Ziercke told the AP news service. "Tht worries us."

He added that the summit would be one of the biggest security deployments in German history.

Security plans underway

"The Federal Criminal Police will deploy more than 1000 people, and state and local police will put well over 10,000 employees on the case," Ziercke told AP.

According to Lorenz Caffier, interior minister of Mecklenburg-Vorpomerania, the eastern German state hosting the summit, officials will soon begin building a security fence around the upscale Heiligendamm resort, including cameras and motion sensors.

Mecklenburg-Vorpomerania Governor Harald Ringstorff said he is also committed to giving summit opponents a platform for peaceful protest.

"Some of the criticism is absolutely justified," he told German news agency dpa.

Germany will take over the leadership of the G8 in January.