ATHENS, Greece (AP) — An object thrown at the perimeter fence of the Russian Consulate in Athens was a hand grenade that exploded without causing any injuries, Greek police said Friday.

Authorities sent a bomb disposal team to the consulate after cameras showed two people on a motorbike throwing a small object in the early hours of Friday morning at the fence beside the consulate's security guard post, reportedly causing minor damage. Police cordoned off the area around the consulate, located in a suburb north of the city center.

Authorities were examining whether a motorbike found partially burned in a central Athens neighbourhood was related to the incident.

Greece has a long history of small groups that periodically attack symbols of state authority, wealth or foreign diplomacy. They usually plant small explosive devices that don't cause injuries.

Police officials, speaking on condition of anonymity as the investigation was ongoing, said they suspect the attack was carried out by a leftist militant group called the Popular Fighters Group, which had claimed responsibility for a bombing against the offices of a television station and newspaper in December.

The group, known by its Greek acronym OLA, is considered responsible for several bombings and shootings since it first appeared in 2003, when it fired shots at the offices of Greece's conservative New Democracy party.

It has also carried out shootings against the residence of the German ambassador in Athens, fired a rocket against the offices of a car dealership and planted bombs outside the offices of Greece's federation of enterprises, a bank and a courthouse.

None of its attacks have caused any injuries.