WASHINGTON (Reuters) - Several Planned Parenthood officials and three private bio-medical firms were targeted on Friday by a U.S. congressional panel as lawmakers dig deeper into a controversy swirling around the women's health organization.

A U.S. House of Representatives committee made public a letter requesting interviews with personnel from the organization who appeared in surreptitiously recorded videos in discussions about providing fetal tissue for research.

House Energy and Commerce Committee Republicans also said they had written to three companies identified as human fetal tissue suppliers to request information and briefings.

Lawmakers on the committee said last month they would investigate after the videos were released by an anti-abortion activist group called the Center for Medical Progress.

The videos purport to show Planned Parenthood officials negotiating prices for aborted fetal tissue. Under federal law, donated human fetal tissue may be used for research, but profiting from its sale is prohibited. Compensation for the tissue can cover only the costs of handling it.

Planned Parenthood, which provides healthcare services to millions of women at hundreds of centers nationwide, has denied any wrongdoing. The organization also says abortions make up just 3 percent of its work.

Energy and Commerce's letter to Planned Parenthood President Cecile Richards requested "informal interviews" with Dr. Mary Gatter, Dr. Savita Ginde, and Melissa Farrell. It identified Gatter as president of the organization's Medical Director's Council; Ginde as vice president and medical director of Planned Parenthood of the Rocky Mountains; and Farrell as director of research for Planned Parenthood Gulf Coast.

"As you know, in several recent videotapes made public, these individuals have made statements concerning the manner in which fetal tissue is procured," the committee letter said.

"We are examining whether these statements ... are consistent with existing laws," said the letter, signed by the panel's chairman, Representative Fred Upton, and others.

A Planned Parenthood official said the organization had the letter, and would continue to cooperate fully with the committee.

Letters also went to three companies that provide fetal tissue to medical researchers, seeking information on the tissue collection and sale or donation, including pricing.

The companies were Advanced Bioscience Resources, Inc.; Novogenix Laboratories, and StemExpress. All three are based in California; none responded to requests for comment from Reuters.

Energy and Commerce is one of at least three congressional committees investigating Planned Parenthood in the wake of the videos. Some conservative Republicans also want to cut off Planned Parenthood's federal funds.

(Reporting by Susan Cornwell; Editing by Kevin Drawbaugh and Lisa Shumaker)