German officials say they will shut down airspace over northern Germany Wednesday, because of the ash cloud from Iceland's Grimsvotn volcano.

Experts say the cloud reached Scotland Tuesday. It is expected to move east over Scandinavia, The Netherlands and northern Germany Wednesday.

It is not clear how many flights in and out of Germany will be affected. But forecasters in Iceland say the plume of ash being blown out of the volcano has slowed.

Airlines grounded about 500 flights in and out of Britain Tuesday. There also were minor disruptions in Norway and Denmark.

Last year's eruption of a different volcano on Iceland forced thousands of flights to be cancelled, wrecking travel plans for millions and costing airlines nearly $2 billion in losses.

Experts warn that flying into a volcanic ash cloud could damage jets and cause engines to stall in mid-air.