Cummins' departure has Democrats particularly riled. The Justice Department has acknowledged that Cummins was fired in order to make room for Tim Griffin, an Arkansas native, Iraq war veteran and former aide to White House adviser Karl Rove.

Griffin was named interim U.S. attorney for the Eastern District of Arkansas in December.

Cummins and five other fired prosecutors were subpoenaed to testify Tuesday before a House Judiciary subcommittee. He also spoke to the Senate Judiciary Committee under threat of a subpoena from that panel.

Cummins said he attempted to stay out of the political fray until it appeared his job performance was being called into question. As a result, he granted interviews to national news organizations.

One article in the Washington Post prompted Elston's call, and Cummins' relaying Elston's message to the other prosecutors.

"If they feel like any of us intend to continue to offer quotes to the press, or organize behind-the-scenes congressional pressure, then they would feel forced to somehow pull their gloves off and offer public criticisms to defend their actions more fully," Cummins said in his e-mail released by the Senate Judiciary Committee.

David Iglesias, former prosecutor in New Mexico, said he thought the account of Elston's conversation was "a warning shot across the bow."

Cummins, however, tempered his comments under questioning from Sen. Arlen Specter, R-Pa., the ranking Republican on the judiciary panel. He said the phone conversation also could be perceived as friendly and did not warrant any criminal investigation.

The Justice Department did not return a call seeking comment. However, a department spokesman told the Associated Press that Elston did not try to curtail prosecutors' comments.

"A private and collegial conversation between Mike Elston and Bud Cummins is now somehow being twisted into a perceived threat by former disgruntled employees grandstanding before Congress," Spokesman Brian Roehrkasse told the AP.

Iglesias said he thought his firing was tied to a reported investigation of Democrats in New Mexico that was a big campaigin issue in the state last fall.

He received phone calls from Sen. Pete Domenici, R-N.M., and Rep. Heather Wilson, R-N.M., in October regarding the investigation, with Domenici inquiring whether indictments might be issued before November -- and hanging up when Iglesias said they probably would not be.

He was fired five weeks later.

"I felt leaned on," Iglesias said. "I felt pressure to get these matters moving."