The European Union's antitrust office spelled out its objections Monday to a proposed merger of the music units of Japan's Sony Corp. and Germany's Bertelsmann AG, giving the companies two weeks to respond.

Amelia Torres -- a spokeswoman for the European Commission, the EU's executive arm -- confirmed the objections had been sent but declined to elaborate.

Bertelsmann said it was examining the EU's "remaining concerns" about the proposed 50-50 joint venture.

"Bertelsmann welcomes the clarity this step will give to the debate and remains confident about demonstrating, in addressing the remaining concerns, that the merger will not impede competition," it said in a statement from its base in Guetersloh, Germany.

In a separate statement, Sony said it planned "on working closely" with the EU to resolve the concerns and was confident the antitrust office would ultimately approve the deal.

Under EU rules, the companies have two weeks to respond in writing. They also are entitled to face off with commission lawyers and industry rivals at a closed-door hearing, which has been penciled in for June 14-15 if requested.

The European Commission has until July 22 to decide on the deal.

A statement of objections is a standard step in EU antitrust reviews and usually results in divestitures or other commitments from the companies involved to win approval.

The statement had been expected last week but was delayed a few days.

The merger would leave four companies with about 80 percent of the global music market, raising fears of increased chances for market dominance. Similar concerns derailed a deal between music giants EMI Group PLC and Warner Music Group Inc. four years ago.

As in that case, small independents are opposing the deal. Apple Computer Inc. has also criticized the Bertelsmann-Sony deal because Sony is launching an online distribution network that could rival Apple's iTunes service.