BERLIN — Authorities have found an unexploded ***** *** II **** by a highway close to Frankfurt airport and an operation to defuse it may cause flight disruptions.

The 500-kilogram British **** was found during construction work and ****** were working to defuse it Tuesday evening. One runway at the airport — Germany’s busiest — was closed for landings because planes weren’t allowed to fly directly over the site, news agency dpa reported.

Landings were expected to be suspended altogether for at least a short time, it said, citing air traffic control.

A stretch of the A3 highway near Offenbach, outside Frankfurt, was also closed.

Allied airplanes dropped millions of tons of ordnance on Germany during ***** *** II. Unexploded bombs are still found frequently.