The two ex-Infinity Ward bosses sensationally sacked by Call of Duty publisher Activision earlier this week have hit back at the publisher, claiming they are owed "substantial royalty payments".

According to a press release issued by their lawyers, Jason West and Vince Zampella are suing to regain control of all Modern Warfare-branded games.

Activision shocked the gaming world when it axed West and Zampella, the two men at the heart of the phenomenally successful Call of Duty series, following an alleged breach of contract and "insubordination".

It then announced plans to shake up the Call of Duty series, confirming the launch of a Call of Duty game later this year, one next year, and another "action adventure" game from newly-formed studio Sledgehammer Games.

According to the press release, Activision terminated West and Zampella's employment weeks before they were to be paid substantial royalty payments as part of their existing contracts for Modern Warfare 2.

"Activision has refused to honour the terms of its agreements and is intentionally flouting the fundamental public policy of this State (California) that employers must pay their employees what they have rightfully earned," said their attorney Robert Schwartz.

"Instead of thanking, lauding, or just plain paying Jason and Vince for giving Activision the most successful entertainment product ever offered to the public, last month Activision hired lawyers to conduct a pretextual 'investigation' into unstated and unsubstantiated charges of 'insubordination' and 'breach of fiduciary duty,' which then became the grounds for their termination on Monday, March 1st."

"We were shocked by Activision's decision to terminate our contract," said West. "We poured our heart and soul into that company, building not only a world class development studio, but assembling a team we've been proud to work with for nearly a decade. We think the work we've done speaks for itself."

Zampella added: "After all we have given to Activision, we shouldn't have to sue to get paid."

The press release includes more juicy detail on what's fast-becoming the gaming story of 2010.

It says: "Activision seized control of the Infinity Ward studio, to which Activision had previously granted creative control over all Modern Warfare-branded games.

"The suit was filed to vindicate the rights of West and Zampella to be paid the compensation they have earned, as well as the contractual rights Activision granted to West and Zampella to control Modern Warfare-branded games.

"The suit includes claims for breach of contract, breach of the implied covenant of good faith and fair dealing, wrong termination in violation of public policy, and declaratory relief."

While Infinity Ward's future as a Call of Duty developer beyond the release of the "first two" map packs for Modern Warfare 2 remains unclear, an internal Activision memo written by Activision publishing president and CEO Mike Griffith said Infinity Ward "remains central" to Call of Duty's future.