WASHINGTON — Republicans could face ethics investigations for contacting U.S. attorneys about pending cases, a jarring political development only four months after ethical lapses helped cost the GOP control of Congress.

Two veteran Republican lawmakers and a top GOP leadership aide contacted prosecutors who later were fired. All three denied wrongdoing.

Democratic-run committees in both the House and Senate are investigating the firings of eight U.S. attorneys. Six of those prosecutors told Congress on Tuesday they felt pressured by the interventions.

The Senate ethics committee already is conducting a preliminary inquiry into the call by Sen. Pete Domenici, R-N.M., to a prosecutor in his state. The action was required once the committee received a complaint against Domenici from a congressional watchdog group.

The House's ethics panel has more discretion on starting an initial inquiry. But Majority Leader Rep. Steny Hoyer, D-Md., said there should be one. Rep. Heather Wilson, R-N.M., contacted the same prosecutor as Domenici.

Edward Cassidy, a top aide to House Republican leader John Boehner of Ohio and a former ethics committee staff member, contacted a prosecutor in Washington state.

The Senate's ethics manual says Senate offices should refrain from intervening in pending court actions "until the matter has reached a resolution in the courts." The House's version has similar warnings.

Cassidy's case presents a potential conflict for the senior Republican on the House ethics committee, Rep. Doc Hastings of Washington state. Cassidy was his top aide in his personal office and on the committee.

Hastings normally would play a crucial role in the evenly divided committee, in deciding whether to begin an initial investigation and appointing an investigative subcommittee. He would not comment Tuesday on whether he planned to remove himself from any committee decisions.

Hoyer, a key architect of the Democrats' takeover of the House, expressed no reluctance to jump on the new Republican dilemma.

"When issues are raised in the public sphere, I think the committee has a responsibility on its own, and I would hope they would do that," Hoyer told reporters.

Democrats made GOP ethical misdeeds a major issue in the fall campaign. They singled out former GOP Majority Leader Tom DeLay, the subject of several ethics probes, and were handed a pre-election scandal when it was disclosed that former Rep. Mark Foley, R-Fla., made advances to former male teenage pages.

The firing of eight U.S. attorneys has raised questions about how they are appointed and the circumstances under which they may be dismissed. Last year's renewal of the USA Patriot Act, the Bush administration's prime anti-terror law, contained a provision that abolished limits on how long interim prosecutors may serve.

Democrats have accused the Justice Department of seeking to use the provision to bypass the Senate confirmation process. Legislation has been introduced to reverse that provision.

The fired prosecutor from New Mexico, David Iglesias, told senators he had a brief telephone conversation with Domenici in late October 2006 that ended when Domenici abruptly hung up. Iglesias said he had just told the senator that indictments in a corruption case against Democrats would not be handed down before the November elections.

Iglesias also said he received a call from Wilson before the election, in which she asked him about sealed indictments — a topic prosecutors cannot discuss. Wilson's question "raised red flags in my head," Iglesias said.

John McKay, the fired U.S. attorney in Seattle, said he stopped Cassidy — the Hastings assistant — from asking him detailed questions about an investigation into the disputed election of Washington state's Democratic Gov. Christine Gregoire in 2004.

Domenici had a much different recollection than Iglesias about his call to the prosecutor.

He said in a statement that Iglesias "confirmed that our conversation was brief and that my words did not threaten him, nor did I direct him to take any course of action. While I recall, as I stated previously, that I asked Mr. Iglesias about timing of the investigation, neither I nor those who overheard my side of the brief conversation recall my mentioning the November election to him."

Wilson said she called the prosecutor after a constituent "with knowledge of ongoing investigations" told her that Iglesias was intentionally delaying corruption prosecutions.

"I called Mr. Iglesias and told him the allegation, though not the source," she said. "Mr. Iglesias denied delaying prosecutions. He said he had very few people to handle corruption cases. I told him that I would take him at his word, and I did. "

She added, "If the purpose of my call has somehow been misperceived, I am sorry for any confusion."

Hastings defended his former aide, saying Cassidy's call was "a simple inquiry and nothing more" about Washington state's close gubernatorial election.

Cassidy called his call to McKay "a routine effort to determine whether allegations of voter fraud in the 2004 gubernatorial election were, or were not, being investigated by federal authorities."

"As the top aide to the chairman of the House ethics committee, I understood the permissible limits on any such conversation," Cassidy said.