The Department of Justice filed a civil lawsuit Wednesday in New Orleans against the oil giant BP and eight other companies over the oil spill in the Gulf of Mexico.

Although the complaint does not specify the damages that the administration is seeking, the fines and penalties under the laws that are cited in the complaint could reach into the tens of billions of dollars.

“We will not hesitate to take whatever steps are necessary to hold accountable those who are responsible for this spill,” Attorney General Eric H. Holder Jr. said at a news conference.

Mr. Holder said the department was “making progress” on a criminal investigation of the companies involved in the spill.

The Deepwater Horizon rig burned and sank in April, killing 11 workers and leaving the well it was drilling to gush out of control on the gulf floor. Millions of gallons of crude oil spilled before the well was capped in July.

The government is alleging violations of federal regulations concerning the operation and safety of oil rigs, including the failure to take necessary precautions in securing the rig before the explosion and the failure to use the safest drilling technology.

The nine defendants include BP and its partners in owning the well, Anadarko Petroleum and MOEX Offshore 2007, as well as BP’s operating partners, including Transocean, the owner of the rig, and insurers. The 27-page complaint was filed in Federal District Court in New Orleans, where thousands of spill lawsuits have been consolidated.

A leader of the group of plaintiffs’ lawyers in the case, James Roy, welcomed the newest litigant, saying, “We look forward to continued cooperation with the U.S. government in pursuit of justice for all victims of the Deepwater Horizon tragedy.”

Halliburton, the contractor for the cement work on the well, was not named as a defendant, but Mr. Holder said the complaint could be amended later. The complaint specifically cites failures of cementing as a factor that contributed to the spill.

David M. Uhlmann, a law professor at the University of Michigan, said the filing had been expected. “The only question,” he said, “has been when, not if, a civil suit would be filed.”

Professor Uhlmann, who led the environmental crimes section of the Justice Department during the George W. Bush administration, called the filing “the opening salvo in the government’s response to the gulf oil spill.” Although the suit could subject BP and the other companies to billions of dollars in civil penalties and natural resource damage claims, he said the next act could be even more dramatic: a criminal case, he said, would “bring the most significant penalties and provide the most meaningful accountability for this tragedy.”

Scott D. Dean, a spokesman for BP, said the filing “does not in any manner constitute any finding of liability or any judicial finding that the allegations have merit.” The company, he said, will continue to work with the government, and he noted that BP had created a $20 billion fund to pay “all legitimate claims” from the spill, “before any legal determination of responsibility and will continue to fulfill our commitments in the gulf as the legal process unfolds.”

Transocean denied liability in a statement, saying that the company followed “calculations, blueprints and step-by-step construction procedures” from BP that federal regulators approved. Responsibility “lies solely with the well’s owner and operator,” the company said.

John Christiansen, a spokesman for Anadarko Petroleum, which owns 25 percent of the well, also placed the blame on BP in an e-mailed statement. He said that in the case of gross negligence or willful misconduct, the operating agreement between BP and the other owners places the liability with BP — and, he said, “the operator’s decisions and actions on the rig likely amount to gross negligence and/or willful misconduct.”

A spokesman for MOEX, which owns 10 percent of the well, said that the company was reviewing the filing, but added that MOEX “had no authority or responsibility to direct activities on the Deepwater Horizon.”

A member of Congress who has been sharply critical of BP applauded the lawsuit. Representative Edward J. Markey, a Democrat of Massachusetts, said: “It may have taken these companies months to cap their well, but they will spend years trying to cap their financial obligations to the people of the gulf.”

Liz Robbins contributed reporting.