WASHINGTON — The computer phishing scam that Google says originated in China was directed at an unknown number of White House staff officials and set off the FBI inquiry that began this week, according to several administration officials.

It is unclear how many White House staff members — or those of other departments in the executive branch — might have been targeted, according to two officials with knowledge of the investigation. But the intended victims ranged across different functions in the White House, and were not limited to those working on national security, economic policy, or trade areas that would be of particular interest to the Chinese government.

Administration officials said they had no evidence any confidential information was breached, or even that many people fell for the attack by providing information that would allow a breach of their Gmail accounts. White House classified systems run on dedicated lines and information on those systems, the officials said, cannot be forwarded to Gmail accounts. But investigators are trying to determine if the attackers believed that some staff members or other officials used their personal e-mail accounts for sensitive government communications.

“Right now,’’ said one senior official, “that’s a theory, not a fact.’’

Google disclosed the attack this week and said it targeted not only US government officials, but also human right activists, journalists, and South Korea’s government. Google tracked the attack to Jinin, China, which is the home to a Chinese military school.

But that does not necessarily mean the attackers were Chinese or related to the government. The Chinese government denied any involvement.

The attack used e-mails that appeared to be tailored to their targets to better fool their victims. Recipients were asked to click on a link to a phony Gmail login page that gave the hackers access to their personal accounts.

© Copyright 2011 Globe Newspaper Company.