WASHINGTON (CNN) -- The FBI is investigating whether baseball great Roger Clemens perjured himself in testimony before the House Oversight and Government Reform Committee earlier this month, government officials told CNN on Thursday.
The FBI will also probe whether his former personal trainer, Brian McNamee, lied in testimony to the same committee, the officials said.
"The request to open an investigation into the congressional testimony of Roger Clemens has been turned over to the FBI and will receive appropriate investigative action by the FBI's Washington field office," agency spokesman Richard Kolko said.
In the February 13 hearing, the former New York Yankees pitcher adamantly denied taking performance-enhancing substances, while McNamee testified he injected Clemens with anabolic steroids or human growth hormone.
In an affidavit, former teammate Andy Pettitte also told the committee that Clemens had admitted using the growth hormone.
On Wednesday, leaders of the House committee asked the Justice Department for the perjury probe, saying Clemens' insistence under oath that he never took performance-enhancing drugs raises "significant questions" about the honesty of the seven-time Cy Young Award winner.
Reps. Henry Waxman and Tom Davis, the chairman and ranking Republican on the committee, told Attorney General Michael Mukasey that Clemens' testimony "warrants further investigation" and suggested federal agents "may have access to additional evidence on these matters."
"We are not in a position to reach a definitive judgment as to whether Mr. Clemens lied to the committee," the two lawmakers wrote in a Wednesday letter to Mukasey. "Our only conclusion is that significant questions have been raised about Mr. Clemens' truthfulness and that further investigation by the Department of Justice is warranted."
Clemens' attorney, Rusty Hardin, has said his client will "continue to fight these false allegations with every ounce of strength he has." On Wednesday, after the Waxman-Davis letter was released, Hardin said their request was "unwarranted and not supported by the facts."
In a statement Thursday, he said word of the FBI investigation came as no surprise.
"We've always expected they would open an investigation," Hardin said. "They attended the congressional hearing. So, what's new?"
The committee has already asked the Justice Department to investigate perjury charges against Houston Astros infielder Miguel Tejada.
Tejada denied using performance-enhancing drugs during a 2005 hearing, but a report from the Mitchell Commission, a Major League Baseball probe into steroid use headed by former Sen. George Mitchell, linked him to use of the substances in its December report.
Clemens, 45, returned to the Yankees in 2007 after a brief retirement, but says he is now retired. In his five-hour appearance before the committee, he told lawmakers he received only vitamin shots from McNamee.
McNamee told the Mitchell Commission he injected Clemens on 16 occasions with steroids, testosterone or human growth hormone. He told the committee earlier this month he saved physical evidence, including gauze pads and syringes, to back up his statements.
Questioning during the committee hearing was largely split along partisan lines, with Republicans focusing on McNamee and Democrats on Clemens. But in a statement, Davis said the committee has evidence contradicting Clemens' testimony, and "the only responsible course was to refer the matter to the law enforcement authorities charged to determine whether laws were broken."
Hardin has said Clemens is prepared to face a perjury probe. "The fact that he chose to testify twice under oath while knowing the short-term consequences is clear proof of how strongly he believes he has done nothing wrong."
Pettitte, meanwhile, admitted using growth hormone twice, in 2002 and 2004. In a sworn statement to the House committee, he said Clemens admitted using the hormone during a conversation the two had in 1999 or 2000.
Clemens said Pettitte "misheard" the conversation.
The committee asked prosecutors to investigate whether McNamee injected Clemens with lidocaine in 1998; whether trainers from all four of his teams gave him pain injections; whether vitamin B-12 injections were regularly administered to him; and whether Clemens and McNamee ever talked about human growth hormone.
Other evidence to be explored, according to the Waxman-Davis letter, involves whether Clemens was at a 1998 party at the Miami, Florida, home of fellow ballplayer Jose Canseco, and whether he was ever notified that Sen. George Mitchell asked to meet with him in connection with the baseball probe. E-mail to a friend
CNN's Kevin Bohn contributed to this report.