WASHINGTON, D.C. ? A United Arab Emirates company formally submitted Friday to an unusual, broader security examination of its plans to assume significant operations at six major U.S. ports – a business deal it code-named “Project Thunder.”

The Bush administration said it will conduct a new, 45-day investigation of plans by Dubai-owned DP World to purchase London-based Peninsular & Oriental Steam Navigation Co. for $6.8 billion.

The Project Thunder code name refers to a Dubai-controlled subsidiary, Thunder FZE, that is participating in the complex transaction, according to documents previously submitted to the Homeland Security Department.

The new investigation is aimed at quieting the furor in Washington over the administration’s earlier approval of the deal. The British company runs major port operations in New York, New Jersey, Baltimore, New Orleans, Miami and Philadelphia.