European Union antitrust regulators charged U.S. chipmaker Qualcomm on Tuesday of using anti-competitive practices to block rivals.

The accusations by the European Commission set out in a charge sheet known as a statement of objections followed a formal investigation begun in July.

"The Commission informed Qualcomm of its preliminary conclusions that the company may have illegally paid a major customer for exclusively using its chipsets and sold chipsets below cost with the aim of forcing a competitor out of the market," the EU executive said.