WASHINGTON (AP) _ The Justice Department filed suit Tuesday to block the proposed $129 billion merger of WorldCom and Sprint, the nation's second- and third-largest phone companies, on grounds it would increase prices for millions of consumers.

The companies almost immediately withdrew their merger notification filed with the European Commission, citing Justice Department opposition.

``If, in the future, the parties decide to proceed with the merger, they will make such notifications as are appropriate under European merger laws,'' WorldCom and Sprint said in a joint news release.