BEIJING, Sept. 2 -- China's ongoing investigations into foreign companies are "open and fair", a Foreign Ministry spokesman said Tuesday.

Asked to comment on whether U.S. firms are facing a worsening investment environment in China, spokesman Qin Gang said the involved departments are fully following China's laws as they conduct antitrust survey.

"The anti-monopoly (law) is not one that exists only in China, it exists in every other country," Qin told a daily press briefing, adding that China's act aims at safeguarding consumers' interests and making the competitive market more open, fair and impartial.

"China will as always welcome foreign corporations to participate in the Chinese market, " Qin said. "China is ready to offer sound market conditions; meanwhile, we also require they obey Chinese laws."