(Reuters) - The National Football League has filed a lawsuit against nearly three dozen insurance companies, seeking to force them to defend the league against mounting brain injury claims by former players and their families.

The suit, filed late Wednesday in Los Angeles Superior Court, names virtually every major insurer in the country, led by the Allianz-owned Fireman's Fund. All the firms were involved in coverage for the league or its affiliates at some point between the late 1960s and today.

The NFL said it was a defendant in at least 143 bodily or personal injury suits, and that its insurers were obligated to defend the league under its general liability policies, which the group said they had not provided.

"As a direct and proximate result of said insurers' breach of their contractual duty to defend the NFL and NFL Properties in and against the injury lawsuits, Plaintiffs have suffered damages in attorneys' fees and other costs incurred to defend against those suits," the NFL alleges in its complaint, adding it was entitled to at least $5 million in damages.

A spokeswoman for Fireman's Fund was not immediately available to comment on the complaint.

Retired players in increasing numbers are taking action against the NFL over brain injuries they claim to have suffered playing football. At least some of the suits allege the league deliberately and fraudulently concealed the risks of injury, a charge it vehemently denies.

Several retired NFL players have committed suicide in recent years by shooting themselves in the chest, in some cases with the explicit goal of preserving their brains for study.

The case is National Football League et. al. vs. Fireman's Fund Insurance Co. et. al., California Superior Court, Los Angeles County, No. 490342.