The two sources said the following companies were at the hotel: GE, Siemens, Samsung Electronics, Microsoft, Volvo, IBM, Michelin; Swedish packaging giant Tetra Pak; Intel; Qualcomm; Dumex, a subsidiary of France's Danone; and U.S. cable equipment maker Arris Group.
Tetra Pak confirmed it was there but declined to comment further. Samsung and Volvo said they were not aware of any meeting. IBM, Intel, GE and Microsoft declined to comment. Siemens, Arris, Michelin and Dumex did not respond to questions, while Reuters was unable to immediately reach Qualcomm. Reuters does not have a full list of firms at the meeting.
The government agencies held a separate training session for Chinese state-owned enterprises around the same time, one of the sources said, though it was unclear what was discussed.
The two sources said Xu did not explain why he didn't want foreign firms to hire external lawyers if they were investigated.
Getting an admission of guilt from companies makes it easier for the NDRC because lawyers who have dealt with it said its capacity for legal analysis was weak and that few within its antitrust bureau had a background in law.
(Read more: Dodgy data may add $1 trillion to Chinese economy: Report)
"They don't do analysis. They just do an interview and ask for an admission," said one lawyer from a leading antitrust firm in China who also had direct knowledge of the July meeting.
When one lawyer asked a question about the anti-monopoly law, Xu asked the executive to elaborate on his company's practices so he could determine on the spot if it was in violation or not, the two sources said. The lawyer clammed up, they said.
While Chinese regulators have said little to explain the motivations behind the various pricing investigations, state media have accused the foreign media of exaggerating the issue.
In a commentary Monday, the official Xinhua news agency said such inquiries were routine in a market-oriented economy.
"The battle is not targeted at foreign companies. It is aimed at creating a fairer, cleaner and better-regulated environment for economic competition," the English-language commentary said. "Probing and punishing ill-behaved companies will increase the confidence of international firms in the Chinese market, not the other way round."