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WASHINGTON (CNN) - The House Ethics committee announced Thursday it is looking into allegations of possible misconduct by members of Congress regarding The PMA Group, a now-defunct lobbying firm.

PMA, which was raided by the FBI last year, lobbied primarily on behalf of defense-industry clients seeking earmarks. The company and its clients donated campaign contributions to senior members of the House Appropriations Committee, including Rep. Jack Murtha, D-Pennsylvania, and Rep. Pete Visclosky, D-Indiana.

The Ethics Committee did not disclose which specific lawmakers were under review.

The committee's announcement follows a vote last week by the House requiring the committee to disclose what actions, if any, it was taking on PMA.

In a written statement, Ethics Committee Chair Zoe Lofgren, D-California, and ranking Republican Jo Bonner, R-Alabama, said the committee had "authorized a review of certain, specified allegations within the committee's jurisdiction that relate to the subject of the resolution."

"I'm encouraged that the Ethics Committee is looking into the PMA scandal," said Rep. Jeff Flake, R-Arizona, in a statement. "Obviously, with the first appropriations bill scheduled to be on the floor next week, the House of Representatives cannot justify the continued practice of awarding no-bid contracts to private companies. This announcement ought to be a sign that this practice needs to stop immediately."

Flake, a longtime critic of earmarks, has repeatedly tried to pass a resolution telling the committee to investigate PMA, but his attempts were blocked by Democrats.

Earlier this month, Visclosky acknowledged he received a subpoena from federal prosecutors for material from his campaign and congressional offices regarding PMA. Visclosky, who chairs a key panel on the House Appropriations Committee, maintained he has done nothing improper and pledged to cooperate with investigators.

Murtha also has denied any wrongdoing.