(Bloomberg) -- Cigna Corp. sued its merger partner Anthem Inc. after ending their $48 billion agreement, a deal that had been blocked by a U.S. judge. Anthem, minutes later, said Cigna had no right to terminate the deal.

In a statement, Cigna said its complaint seeks payment by Anthem of the $1.85 billion reverse termination fee included in the merger plan. The move further escalates the discord between the two U.S. health insurers, whose merger had been riven with clashes for months.

In its own statement, Anthem said it had extended the proposal through April 30 after the deal was blocked. Cigna’s purported termination of the agreement is “invalid,” Anthem said.

The announcements came just hours after the other U.S. health-insurance megadeal, between Aetna Inc. and Humana Inc., ended peacefully when the companies mutually decided to walk away from their agreement.

To contact the reporter on this story: Cecile Daurat in Wilmington at cdaurat@bloomberg.net.

To contact the editor responsible for this story: Drew Armstrong at darmstrong17@bloomberg.net.

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