UPDATE 1-RIM sues Motorola for blocking job offers

* RIM sues Motorola for blocking job hires

* RIM alleges Motorola practices "unfair competition"

* Suit filed three months after Motorola sued RIM (Adds details from lawsuit, BOSTON dateline)

BOSTON, Dec 24 (Reuters) - Research In Motion Ltd (RIM.TO) is suing Motorola Inc (MOT.N), alleging that the mobile phone company improperly blocked the BlackBerry maker from hiring current and laid-off Motorola employees.

The suit, filed in state court in Chicago on Tuesday, comes three months after Motorola alleged that RIM violated an agreement reached in February that the two companies would not solicit each other's employees.

RIM asked for a court order to invalidate the agreement, saying in its complaint that the pact had expired in August and was no longer enforceable.

The Canadian company is also seeking unspecified damages for what it called "unfair competition" practices by Motorola.

Motorola spokeswoman Jennifer Weyrauch-Erickson declined to comment on the lawsuit.

"RIM entities continue to grow and hire new employees within the United States and globally against a backdrop of recent public announcements by Motorola that it has and will continue to make massive layoffs," said RIM's lawsuit.