WASHINGTON (REUTERS) - A second United States Senate committee on Wednesday (March 27) sought to examine the motives of federal agents and investigators who launched the Trump-Russia probe as a Republican effort gathered momentum to seek retribution on behalf of President Donald Trump.

Homeland Security chairman Ron Johnson told Reuters he planned to join Senate Judiciary chairman Lindsey Graham, a fellow Republican, in a review of what motivated an investigation that led to Special Counsel Robert Mueller's 22-month probe of Russian meddling in the 2016 election and possible collusion with the Trump campaign.

"How was this pushed by members of the FBI, Department of Justice and the intelligence community? We're fully aware of the bias that existed in those agencies under the Obama administration," Mr Johnson said, referring to Democratic president Barack Obama, who preceded Mr Trump.

"I've been talking to Senator Graham. I want to work hand-in-glove, our two committees, to try and get that information and make it public for the American people," he said.

Mr Trump, who, along with fellow Republicans, has seized on the disclosure that Mr Mueller did not find his campaign conspired with Russia to meddle in the election, has been calling for investigations into how the probe got started.

"He is on fire. Anybody who thinks this is going to go by the wayside does not understand the issue of retribution," said a Trump confidant who speaks to the President regularly. "Hell hath no fury like a president scorned."

Trump advisers predict Mr Trump will make much of the matter at a rally for supporters in Grand Rapids, Michigan, on Thursday, his first major appearance since the Mueller investigation concluded.

A Trump ally, Mr Graham laid out plans for his own investigation this week and urged US Attorney-General William Barr to name a special counsel to look into the matter separately.

US House of Representatives Judiciary Committee chairman Jerrold Nadler told reporters he was very concerned that Mr Barr would not submit Mr Mueller's report to Congress by next Tuesday as Democrats had requested. Mr Nadler said he had a 10-minute phone conversation with Mr Barr on Wednesday.

"I asked whether he could commit that the full report, an unredacted full report with the underlying documents evidence would be provided to Congress and to the American people. And he wouldn't make a commitment to that. I am very concerned about that," he said.

Mr Mueller's report was submitted last Friday to Mr Barr, who issued a summary. Mr Trump said he had been completely exonerated, even though the report did not clear him on the question of obstructing justice.

Mr Trump still faces congressional investigations into his personal and business affairs. But Republicans are hoping Mr Mueller's findings will help Mr Trump's 2020 re-election prospects and rebound against his Democratic accusers.

A focus of Republican inquiries is a Foreign Intelligence Surveillance Act warrant for former Trump adviser Carter Page, based in part on information in a dossier compiled by Mr Christopher Steele, a former British intelligence officer who co-founded a private intelligence firm.

Mr Page, a foreign policy adviser during Mr Trump's campaign, drew scrutiny from the FBI, which said in legal filings in 2016 that it believed he had been "collaborating and conspiring" with the Kremlin. Mr Page met several Russian government officials during a trip to Moscow in July 2016. He was not charged.

Mr Johnson also hopes to unearth facts about alleged discussions at the Justice Department both to surreptitiously record conversations with Mr Trump and to approach Cabinet members about replacing him under the US Constitution's 25th Amendment.

Mr Johnson said federal law enforcement officials would have done better to approach Mr Trump quietly about concerns they had involving members of his campaign.

During his investigation, Mr Mueller brought charges against 34 people, including Russian agents and former Trump aides.

Asked about the Republican push to investigate the investigators, Democrat Jamie Raskin of the House Judiciary Committee said: "There is a scramble to obscure the reality that nobody has seen the Mueller report yet."

"So, it was perfectly predictable," he added, "that once they declared the President completely and totally exonerated by a report no one has read, they would turn in vindictive fashion to try to go after the people who raised questions about the President's conduct."