ATHENS, Greece (AP) -- An airship patrolling Athenian skies during the Olympics was grounded Thursday for minor repairs, Greek police said.

Gas was found to be leaking from the blimp's right engine area, but the problem was not thought to be serious, police said.

Police said they hoped the blimp would be flying Friday. When the blimp is not aloft, police have to use more helicopters and aircraft to monitor Athens.

The 60-metre airship has been flying over Athens since July 24 and is part of an electronic blanket over Athens, consisting of more than 1,000 cameras, sensors and other devices. The blimp is equipped with cameras, chemical "sniffers" and other sensors.