United States agents have searched the property of at least 10 suspects as they investigate a security breach at data broker LexisNexis that left thousands vulnerable to identity theft, the FBI said on Thursday.

No charges were filed, but an FBI spokesman said the searches were carried out by federal agents in several states, including California, Minnesota and North Carolina.

The disclosure of the security breach in March further unsettled Americans worried about the privacy of their personal data after a LexisNexis rival, ChoicePoint, revealed a data breach of its own the previous month. Congress is considering greater regulations for the industry.

LexisNexis, a subsidiary of Dutch publishing giant Reed Elsevier, has said hackers used legitimate customer accounts to gain access to profiles of 32,000 people.

The profiles included Social Security numbers and driver's license numbers, which criminals can use in identity fraud.

The company also revealed in April that information on 310,000 U.S. citizens may have been revealed in a string of incidents during the past two years.

Spokesmen for LexisNexis and for the U.S. Secret Service, which also is involved in the investigation, declined to comment on Thursday's FBI announcement.