BERLIN — Officials say Berlin's Staatsoper opera house will not reopen until 2015 after a new problem arose at the building site in the German capital.

City officials announced Friday that the opera's 19th-century home on the Unter den Linden boulevard won't be ready until April 2015.

It's the second delay: a year ago, the reopening was put back by a year to the beginning of the 2014-2015 season.

News agency dapd reported that senior city official Regula Luescher said the latest delay was caused by the unexpected discovery of wooden posts 56 feet (17 meters) under the building, which made changes to the project necessary.

The Staatsoper, under musical director Daniel Barenboim, has moved to a temporary home across town during the restoration work, which started in 2010.