FRANKFURT (Reuters) - A drone sighting on Friday prompted a 30-minute stoppage of air traffic at Frankfurt airport, one of the world’s busiest, an airport spokesman said.

Air traffic was halted from around 5.15 p.m. until 5.45 p.m., the spokesman said.

The incident involved a single drone and flights were back to normal, the airport wrote on Twitter. “No chaos,” it said.

A spokeswoman for Germany’s state-owned DFS air traffic controller said federal police searched the air space with helicopters before deciding to reopen it after 30 minutes.

A federal police spokesman confirmed that a drone sighting had been reported, but the police had so far been unable to confirm there was a drone. No suspects had been identified and the investigation was continuing, he said.

Thilo Vogt, a senior official with DFS, last month said drone sightings reported by pilots nearly doubled to 158 in Germany in 2018.

The incident came after drone sightings caused three days of travel chaos at London’s Gatwick Airport in December, resulting in the cancellation or diversion of about 1,000 flights at an estimate cost of more than 50 million pounds.