The House Judiciary Committee on Thursday asked former White House adviser Karl Rove to testify about claims that he influenced a federal corruption case against former Democratic Gov. Don Siegelman of Alabama.

The panel also called on the Justice Department's inspector general to investigate allegations that political motivations drove the Siegelman case and several other federal prosecutions during the Bush administration.

Issuing a lengthy report on possible "selective prosecution," the committee cited cases against Pennsylvania coroner Cyril Wecht and Wisconsin state procurement official Georgia Thompson as other examples that are ripe for review.

Like the Siegelman prosecution, both cases had political undercurrents, with critics saying they were engineered by White House-appointed prosecutors to hurt Democrats during election season. A judge recently declared a mistrial in the Wecht case, and a conviction against Thompson was overturned last year.

Judiciary Committee Chairman John Conyers, D-Mich., accused Attorney General Michael Mukasey of not taking the allegations seriously and of blocking congressional requests for documents. Conyers said the evidence presented thus far threatens to undermine public faith in the judicial system.

"The Justice Department has simply not been forthcoming, and I feel the only way to move this investigation forward is to seek further independent investigation and testimony from Karl Rove, who appears to be the missing link in a chain from the White House to the Justice Department," Conyers said in a statement.

Peter Carr, a Justice spokesman, said the department was reviewing the report.

"The attorney general, however, has made clear that the department has and carries out a duty to ensure that its investigations of public corruption are conducted without fear or favor, and utterly without regard to the political affiliation of a particular public official," Carr said.

Rove, who was heavily involved in Alabama politics before directing President Bush's White House campaigns, has denied any involvement in the Siegelman case. But calls for his testimony have grown louder since a Republican lawyer and campaign volunteer in Alabama said last year that she overheard conversations among top Republicans suggesting that Rove was pushing Justice officials in Washington to go after Siegelman.

Rove's attorney, Robert Luskin, told MSNBC earlier this month that Rove would testify on the matter. But Luskin said in an interview Thursday that his comments were taken out of context and that the decision was the White House's call, not Rove's, because it involved questions of executive privilege and separation of powers.

The White House had no immediate comment. But administration lawyers so far have refused to allow such testimony — even under subpoena — in a related congressional investigation into whether Bush administration officials fired federal prosecutors who weren't loyal Republicans.

A Judiciary Committee aide said Conyers "reserves the right" to subpoena if Rove denies the request to appear voluntarily.

Vince Kilborn, a Siegelman attorney, called Luskin's argument a "smoke screen."

"Executive privilege does not apply to political activity," he said. "It's not a White House decision. It's his own decision."

Siegelman served one term as governor but was later convicted in 2006 on bribery-related and obstruction of justice charges and sentenced to more than seven years in prison. Last month, a federal appeals court approved Siegelman's release from prison while he appeals, saying the former governor had raised "substantial questions of fact and law."

The prosecution stemmed from his appointment of former HealthSouth CEO Richard Scrushy to an influential hospital regulatory board in exchange for Scrushy arranging contributions to Siegelman's campaign for a state lottery.