(Telecompaper) Mobile operator Zain is being sued for USD 4.5 billion over its 2007 acquisition of an Iraqi telecom operator. Zain bought Iraqna for USD 1.2 billion from Orascom Telecom in December 2007 after the Egyptian firm dropped out of the running for a long-term mobile licence in Iraq. The Kuwaiti firm then merged its Iraqi unit, Atheer, with Iraqna and renamed the entity Zain Iraq, which is now the country's biggest operator by subscribers. Zain said in statement to the stock market that a company it declined to identify filed a lawsuit last August. This claims Zain's takeover had stopped the firm buying Iraqna, causing it losses of USD 4.5 billion, Reuters reports. Zain said it believes its position in the case is strong as the claimant company has failed to produce any evidence to back its claim. The anonymous company is also suing Zain and Iraq's Communications and Media Commission jointly for a further USD 1 billion, the statement said. An Iraqi court in January ruled that all Zain Iraq's revenue from its subscriber base transferred to the company as a result of the Iraqna acquisition should be placed under a legal guardian and in an Iraqi bank until the case is resolved. Zain said it unsuccessfully appealed this decision.