A Brazilian prosecutor is demanding that Chevron and the oil drilling contractor Transocean pay $10.9 billion for a second offshore spill last month, the US oil giant said Wednesday.

The new penalty sought -- 20 billion reals, or $10.9 billion -- "is arbitrary, speculative and not based on facts," Chevron said in a statement sent to AFP.

On March 4, an oil spill was detected at a depth of 1,300 meters (4,200 feet) not far from the site of a bigger spill that occurred last November in the Chevron-operated Frade field located off Rio de Janeiro state.

State prosecutors had already filed legal action against Chevron and Transocean over the November incident, also seeking $11 billion.

"The oil spill from Frade has yet to be contained. The damage to the environment is immeasurable," said state prosecutor Eduardo Santos de Oliveira.

"Each new accident increases the damage and spotlights the mistakes of the accused."

He also called for a freeze on profits made by Chevron in Brazil.

De Oliveira has accused Chevron, Transocean and 17 of their executives of "environmental crimes" in connection with the November spill.

Chevron dismissed the charges as "outrageous and without merit" and vowed to defend itself and its employees.

Brazil's national oil regulator estimated that 2,400 barrels of crude were spilled in the November accident, which led authorities to suspend Chevron's drilling operations and to deny the company access to huge new offshore fields.

Carlos Minc, Rio state's environment secretary, last month slammed Chevron for "unprofessional conduct", saying he favored barring the oil company from operating in Brazil until it pays for the Frade field spills.

To date, the US oil giant has not paid "a single cent" for two fines totaling $54 million set after the November spill, Minc then said.

He said there would be "no impunity" for foreign oil companies operating in Brazil and added: "We must set an example with Chevron."

On Wednesday, a Chevron spokesman said IBAMA, the Brazilian environment ministry's enforcement agency, has slapped a $33 million fine on his company but that the amount of another fine set by the National Petroleum Agency "has yet to be determined" officially.

"The second legal action is part of a series of outrageous moves by the same prosecutor who earlier had already launched equally absurd criminal and civil procedures," Chevron said in a statement.

State prosecutors have said the charges against Chevron are based on "conclusions of the police investigation into the November 7, 2011 accident which occurred because the accused did not respect safety procedures."

They have called for payment of bail of $550,000 for each person accused and $5.5 million for each company.

"These charges are outrageous and without merit," Chevron said in a rebuttal in March.

"Once all the facts are fully examined, they will demonstrate that Chevron and its employees responded appropriately and responsibly to the incident. Chevron will vigorously defend the company and its employees," it added.