European regulators extended their review of Oracle Corp's proposed $7-billion acquisition of Sun Microsystems Inc, giving the software maker more time to address anti-competitive concerns.

The executive European Commission's objections threatened to scuttle the deal.

Oracle requested the extension in order to have the opportunity to further develop its arguments in response to the Commission's concerns, the Commission said on Friday in a daily list of mergers under review.

The Commission, which regulates competition in the 27-country European Union, pushed back its deadline to Jan. 27 from Jan. 19. It gave no further details.

Oracle said in a statement that the review had been extended to accommodate the Nov. 26 U.S. Thanksgiving holiday. The commission postponed a hearing on the matter that had been scheduled for next week.

The Commission said in a preliminary assessment that combining Sun's MySQL product and Oracle's products could hurt competition in the database market, Sun said in a filing with the U.S. Securities and Exchange Commission this month.

Oracle said at the time that it plans to vigorously oppose the Commission's statement of objections.

Sun struck a deal this year to sell itself to Oracle after several years of failed attempts to turn itself around.

The deal was seen as a way to transform the computer maker into a diversified technology company, selling computers alongside Oracle's software.

EU regulators said last month that Oracle had not presented evidence to placate antitrust concerns.

The European Commission's prime concern appears to be Sun's MySQL database, which it bought for $1 billion last year and is used to run popular websites including Google, Facebook and Amazon.

Oracle's database -- the top-selling product in the market -- is far more robust, allowing companies quickly to access larger quantities of data.

Critics of the deal worry Oracle's ownership may hinder MySQL's development.

Oracle shares fell 0.5 percent to $22.27 in morning Nasdaq trade, while Sun shares fell 0.6 percent to $8.55. The Nasdaq Composite Index, by comparison, fell 0.8 percent.

(Additional reporting by Jim Finkle in Boston. Reporting by Dale Hudson, editing by Timothy Heritage and Derek Caney)