Dec. 23 (Bloomberg) -- BlackBerry maker Research In Motion Ltd. sued Motorola Inc. claiming the mobile-phone maker is improperly blocking it from offering jobs to laid-off Motorola workers.

Research In Motion, in a complaint filed today in state court in Chicago, asked for an order invalidating an agreement the companies reached this year not to solicit each other’s employees. The agreement expired in August and is no longer enforceable, according to the complaint.

Motorola, the world’s third-largest mobile-phone maker, is improperly trying to expand the agreement “to prevent the RIM entities from hiring any Motorola employees, including the thousands of employees Motorola has already fired or will fire,” Research In Motion, based in Waterloo, Ontario, said in the complaint.

The lawsuit comes three months after Motorola sued Research in Motion in Chicago in violation of the agreement. In that case, Motorola, based in Schaumburg, Illinois, asked a judge to bar Research In Motion from using Motorola’s confidential information or soliciting or hiring any Motorola employees.

The agreement is part of a February nondisclosure accord under which the companies agreed to exchange information about a confidential matter, the complaint says. Discussions about the matter ended in August without the two companies reaching an agreement.

Kristine Mulford, a Motorola spokeswoman, and Marisa Conway, a spokeswoman for Research in Motion, didn’t respond to voice-mail messages left after hours.

The case is Research in Motion Corp. v. Motorola Inc., 08ch47754, Circuit Court, Cook County, Illinois (Chancery Division).

To contact the reporters on this story: Karen Gullo in Chicago at kgullo@bloomberg.net.

Last Updated: December 23, 2008 20:39 EST