Washington ? A company at the Port of Miami has sued to block the takeover of shipping operations there by a state-owned business in the United Arab Emirates. It is the first American courtroom effort to capsize a $6.8 billion sale already embroiled in a national debate over security risks at six major U.S. ports affected by the deal.

The Miami company, a subsidiary of Eller & Co. Inc., presently is a business partner with London-based Peninsular and Oriental Steam Navigation Co., which Dubai Ports World purchased last week. In a lawsuit in Florida circuit court, the Miami subsidiary said that under the sale it will become an “involuntary partner” with Dubai’s government and it may seek more than $10 million in damages.

The Miami subsidiary, Continental Stevedoring & Terminals Inc., said the sale to Dubai was prohibited under its partnership agreement with the British firm and “may endanger the national security of the United States.” It asked a judge to block the takeover and said it does not believe the company, Florida or the U.S. government can ensure Dubai Ports World’s compliance with American security rules.