A homemade bomb exploded Wednesday near an electrical substation outside the Greek capital, causing damage but no injuries, officials said.

Authorities said it was not immediately clear if there was a link between the blast and the Olympics (search), which open here next week amid unprecedented security.

The device, which police say was made with a cooking gas canister and a triggering fuse, exploded in the bathroom of a building near a substation in the town of Metamorphosi, 6 miles north of Athens (search). No electrical facilities were damaged, a government official told The Associated Press on condition of anonymity.

According to the official, the culprits broke the bathroom window and dropped the device inside. The damage was discovered by an employee of the state power company.

Adequate power for the Olympics became a serious issue after a July 12 blackout that hit the Greek capital and much of southern part of the country.

Homemade explosive devices are frequently set off by anarchist groups and others in Greece, often targeting banks, businesses and diplomatic vehicles. The attacks are mostly carried out at night and rarely cause injuries.