US retail giant Wal-Mart has filed a lawsuit against the Puerto Rican justice department to prevent it from blocking the retailer’s acquisition of a local supermarket chain.

The lawsuit accuses the justice department of discrimination in pursuing an antitrust action to block Wal-Mart’s purchase of AMIGO supermarkets. A Wal-Mart spokesman told a local radio station that the company suspects a different measurement of being used from what has been used in the past. The Wal-Mart lawsuit names as defendant Justice Secretary Anabel Rodriguez, who had confirmed the government’s intention to sue Wal-Mart to apply local antitrust laws, reported AP.

Rodriguez said last week that the deal, reportedly worth US$225m, would contravene Puerto Rico’s antitrust legislation even though the deal has been approved by the US Federal Trade Commission. Puerto Rico is a self-governing commonwealth in association with the US and is subject to US federal laws, reported

Amigo has 37 supermarkets that employ 4,500 on an island with a population of 3.9m people.