HAMBURG, Germany (AP) - People of Hamburg: No drones, no remote controlled airplanes and no hot air balloons either.

Hamburg reminded residents and visitors on Thursday over Twitter that during the Group of 20 summit in the northern port city all such recreational aircraft will be banned from flying.

Police themselves are using drones - both aerial and underwater - as they seek to keep tabs on expected protests.

More than 100,000 protesters are expected to be taking part in multiple demonstrations through the Friday-Saturday summit. Some 20,000 police are also on hand.