Beijing said Wednesday it has been probing two US companies including mobile chipmaker Qualcomm since last year over potential anti-trust violations, extending Chinese investigations of foreign industries to the technology sector.

The confirmation by the National Development and Reform Commission (NDRC), one of China's three anti-trust watchdogs, came after both companies had already acknowledged the investigations.

NDRC official Xu Kunlin discussed the probes Wednesday at a press conference, saying they were launched after separate complaints by unnamed Chinese industry players that the US companies were abusing their market dominance to charge high prices.

Qualcomm, a top maker of smartphone chips, said in November it had been notified the company was the subject of an anti-trust investigation by Chinese authorities and that it was cooperating with the "confidential investigation".

The other probe target, mobile device and technology development company InterDigital, said earlier this month that it "will continue to cooperate with NDRC's anti-monopoly investigation and work with NDRC to resolve any remaining concerns".

Chinese authorities last year launched sweeping investigations into alleged malpractice by foreign firms in various sectors including pharmaceuticals and baby formula.

State television also took to task overseas companies such as technology giant Apple over warranty polices, carmaker Volkswagen AG over quality issues and Starbucks over coffee prices.