European Union regulators have complained about Oracle Corp.'s planned acquisition of Sun Microsystems Inc., suggesting in an initial review that the combination of Oracle database products and Sun's MySQL database could tilt that segment's competitive landscape and result in higher prices.

Oracle, which received regulatory approval from the U.S. Department of Justice in August to proceed with the $7.4 billion acquisition, has until January 27 to address competitive concerns raised by the European Commission, a unit of the EU comprised of 27 commissioners that handles the Union's day-to-day affairs.

Last week, the EU extended Oracle's deadline from the prior January 19^th date, responding to the database maker's request for more time to prepare a rebuttal. Oracle has made it known that it will earnestly contest the EU's objections.

Commission officials said that its objections were based on anti-trust issues and that its evaluation of the deal was ongoing, Reuters news service reported.

The Associated Press reported that Oracle had thus far failed to offer any remedies for the EU's anti-trust charges.

The EU can block the acquisition should Oracle not present a compelling enough case to offset its anti-trust concerns.

Sun lost $120 million in the quarter ended September 27 and in the last year has seen its share of the market significantly pared by rivals IBM Corp. and Hewlett-Packard Co.

Prior to the EU issuing its statement of objections, the Department of Justice took the unusual step of posting a statement re-affirming its approval last summer of the acquisition.

"After conducting a careful investigation of the proposed transaction between Oracle and Sun, the Department's Antitrust Division concluded that the merger is unlikely to be anticompetitive," said Molly Boast, the Department's deputy assistant attorney general.

"At this point in its process, it appears that the EC holds a different view," the Division's statement said.

"The Division concluded, based on the specific facts at issue in the transaction, that consumer harm is unlikely because customers would continue to have choices from a variety of well established and widely accepted database products."