Screen grab from Call of Duty: Modern Warfare 2

The founders of Call of Duty, one of the most successful video game franchises ever, are suing Activision after being forced out of their company.

Jason West and Vince Zampella, two of the founders of Encino, Calif.-based Infinity Ward, announced the lawsuit in a release on Wednesday. They said they were terminated by Activision weeks before they were set to receive royalties for their smash hit Call of Duty: Modern Warfare 2, which has earned more than $3 billion U.S. since its November release.

"We were shocked by Activision's decision to terminate our contract," West said. "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."

Activision has not yet responded to the lawsuit.

The company bought Infinity Ward in 2003 and fired West and Zampella on Monday. Media reports said the decision stemmed from a dispute over the future direction of the Call of Duty franchise. Video game websites have speculated that Activision wants to greatly increase the number of Call of Duty games released while the founders instead wanted fewer titles so they could focus on quality.

Robert Schwartz, a lawyer for West and Zampella at O'Melveny & Myers, said the lawsuit is alleging breach of contract and wrongful termination, among other things.

"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," Schwartz said in a statement.