BRUSSELS (AP) — The European Union's anti-trust watchdog is launching a probe of steel giant ArcelorMittal's planned buyout of Italy's Ilva amid concern the deal could stifle competition and drive up prices.

The EU Commission said Wednesday that it fears "the merger may reduce competition for a number of flat carbon steel products." The commission polices market competition in Europe.

It said ArcelorMittal, which is headquartered in Luxembourg, would boost its market leadership by picking up Ilva's steel plant in Taranto, Italy, the largest of its kind in Europe.

The commission worries that customers in southern Europe could face higher prices, especially for hot rolled, cold rolled and galvanized flat carbon steel products.

EU Competition Commissioner Margrethe Vestager promised an in-depth review. She says: "European industries need access to steel at competitive prices."