A series of firebombings by suspected anarchists in Athens caused damage at a car dealership, a shop and at least three vehicles early Monday, police said.

The six attacks occurred within an hour and were spread over a wide area, police said.

The attacks followed six others 24 hours earlier that damaged two car dealerships, three retailers and a private security company's offices.

For the second night in a row, a Skoda car dealership was targeted; this time, at least three vehicles were destroyed in an explosion caused by multiple gas canisters. Firefighters are still trying to control the blaze.

Skoda is a major supplier of patrol cars to the Greek police.

No group has yet claimed responsibility for the attacks.

The incidents continued a pattern of similar attacks that have increased in frequency since the shooting of a teenager by a police officer on Dec. 6, 2008. Most such incidents occur late at night, but daytime attacks on banks and shops have also occurred.