Hackers operating from China stole sensitive information from Western oil companies, a U.S. security firm reported yesterday, adding to complaints about pervasive Internet crime traced to the country.

The report by McAfee Inc. did not identify the companies but said the “coordinated, covert and targeted” attacks began in November 2009 and targeted computers of oil and gas companies in the United States, Taiwan, Greece and Kazakhstan. It said the attackers stole information on operations, bidding for oil fields and financing.

“We have identified the tools, techniques, and network activities used in these continuing attacks — which we have dubbed Night Dragon — as originating primarily in China,” said the report.

Google Inc. closed its China-based search engine last year after complaining of cyberattacks from China against its e-mail service.

Security consultants say China is a leading center for Internet crime including industrial spying aimed at major companies. Consultants say the high skill level of earlier attacks suggests China’s military, a leader in cyber warfare research, or other government agencies might be stealing technology and trade secrets to help state companies.

The Chinese government has denied it is involved.

Officials in the United States, Germany and Britain say hackers linked to China’s military have broken into government and defense systems. Attacks on commercial systems receive less attention because companies rarely come forward, possibly for fear it might erode trust in their businesses.

McAfee, based in Santa Clara, California, said the hackers worked through servers in the United States and the Netherlands and used techniques including taking advantage of vulnerabilities in the Microsoft Windows operating system.

McAfee said it identified an individual in the eastern Chinese city of Heze in Shandong province who provided servers that hosted an application that controlled computers at the victim companies. The report did not identify the person and said he was not believed to be the scheme’s mastermind.

McAfee said extraction of information occurred from 9 a.m. to 5 p.m. Beijing time on weekdays. It said that suggested the attackers were “company men” on a regular job, rather than freelance or amateur hackers.

The attackers used hacking tools of Chinese origin that are prevalent on Chinese underground hacking forums, McAfee said.