Europe's antitrust chief said Monday he will reject the $115 billion WorldCom-Sprint megamerger unless the companies come up with another plan to ease concern over its combined Internet dominance.

European Competition Commissioner Mario Monti told reporters in Washington, D.C., he could consider accepting late proposals for a remedy but has not received any. June 18 was the deadline for the company to propose new conditions to gain European approval. The European Commission, the administrative arm of the European Union, is expected to vote on the merger July 12. Under a market test, regulators confirm that a remedy would serve competitors and the public interest.EU and U.S. regulators are concerned because the mammoth merger combines the second- and third-largest long-distance companies and dominant Internet backbone providers. WorldCom (stock:WCOM), Clinton, Miss., is focused on acquiring Sprint's wireless system to fill a major hole in its bundle of services, while Sprint (stock: FON), based in Kansas City, Mo., would establish a global footprint. Monti has been in the United States since last week to discuss antitrust transatlantic cooperation, including the WorldCom-Sprint merger. He has met with his counterparts, Attorney General Janet Reno, Assistant Attorney General for Antitrust Joel Klein, and Federal Trade Commission Chairman Robert Pitofsky, and was to confer with Federal Communications Commission Chairman William Kennard later Monday. The European Commission learned lessons from the merger two years ago between MCI (stock: MCIC) and WorldCom that restructuring conditions imposed on the combining companies must be truly effective. To gain approval, MCI sold its Internet assets to Cable and Wireless (stock: CWP), which later litigated the sale as incomplete. Even if the European Commission rejects the merger, the WorldCom and Sprint can resubmit their application and start the process over with new remedy proposals, the European antitrust chief said.