Facebook said some of its applications violated the social networking company's policies against sharing user information, and promised to fix the problem.
Most transfers of information to other companies were inadvertent, Facebook Vice President Marne Levine wrote in a letter released on Wednesday and dated Oct. 29.
Levine in the letter said Facebook would fix the problem.
Facebook sent the letter to Republican Congressmsan Joe Barton and Democratic Congressman Edward Markey, both of whom had written to Facebook CEO Mark Zuckerberg after reports about how third-party applications on Facebook were sharing data.
"We have taken enforcement action against the applications in question, and steps to ensure the deletion of the Facebook user data that was improperly transferred," Levine wrote.
The Wall Street Journal previously reported that FarmVille and other popular Facebook applications transmitted user IDs to outside companies.
Facebook's letter also said a handful of applications intentionally shared information with a data broker.
"The third-party data broker in question has also agreed not to operate on Facebook Platform in the future," Levine wrote. She did not identify the broker or the applications.
Barton, the ranking member of the House Energy and Commerce Committee and in line to run it after Tuesday's Republican election gains, said the panel would focus on Internet privacy policies.
"It's good that Facebook was in a hurry to respond to our concerns, but the fact remains that some third-party applications were knowingly transferring personal information in direct violation of Facebook's privacy promises to its users," said Barton.
Marc Rotenberg, president of the privacy group EPIC, said he was pleased with the Barton-Markey pursuit of Facebook.
"The most recent Barton-Markey letter to Facebook is a powerful signal to the new Congress that privacy will be high on the legislative agenda and that it will have bipartisan support," he said.