Parts of Frankfurt airport were evacuated for several hours on Tuesday following a lapse in security in which a French family of four were allowed to leave the secure zone despite testing positive for explosives, federal police said.

After the alarm had been raised, the family was located in the terminal, re-checked and allowed to continue on their journey after being cleared.

But two gates — A and Z — of the airport's terminal 1 were evacuated and temporarily closed at the airport, a major international hub, disrupting travel during the busy summer holiday season.