Several congressional US Republicans called on Attorney General Jeff Sessions on Thursday to recuse himself from investigations into alleged Russian meddling in the US presidential election after it emerged he met in 2016 with Russia's ambassador but did not disclose the contacts in Senate testimony.

The revelation about Sessions, Republican President Donald Trump's top law enforcement official, rekindled questions about ties between Trump associates and Russia that have dogged the early days of his presidency. They come at a time when Trump and Republicans who control Congress are trying to move past early administration missteps and focus on issues important to them including immigration, tax cuts and repealing the Obamacare healthcare law.

Top Democrats in Congress demanded the resignation of Sessions, who was a close adviser to Trump during his 2016 election campaign, and the appointment of an independent, impartial special prosecutor with no attachment to the Trump administration to examine the Russian role in the election.

Also read US Democrats seek Jeff Sessions resignation after report of Russia contact

House Democratic leader Nancy Pelosi accused Sessions of lying under oath during his Senate confirmation hearing. "The law has been broken," she told reporters. Senate Democratic leader Chuck Schumer said Sessions had misled Congress over his contacts with the ambassador and should resign for the good of the country, adding it would be like "Alice in Wonderland" if the administration were to approve Sessions' investigating himself.

Sessions, a former US senator, received Russian Ambassador Sergei Kislyak in his office in September, the Washington Post reported. The other encounter was in July at a Heritage Foundation event that was attended by about 50 ambassadors, during the Republican National Convention, the Post said.

The US Justice Department confirmed the two meetings, saying they were in Sessions' capacity as a member of the Senate Armed Services Committee and there was nothing untoward about them. Sessions also denied any wrongdoing.

During his confirmation hearing in January, Sessions responded to a question from Democratic Senator Al Franken that he did not "have communications with the Russians" during the course of the presidential campaign.

Allegations over contacts between Trump aides and Russia before his inauguration on January 20, and the charge of Russian election interference which the Kremlin has denied, have swirled around the early days of Trump's presidency. Trump has accused officials in former Democratic President Barack Obama's administration of trying to discredit him.

US intelligence agencies concluded in 2016 that Russia hacked and leaked Democratic emails during the election campaign as part of an effort to tilt the vote in Trump's favour. As attorney general, Sessions heads the Justice Department as attorney general. The FBI, part of the department, has been leading investigations into the allegations of the Russian meddling and any links to Trump's associates.

Republican Jason Chaffetz, chairman of the House of Representatives Oversight Committee, said on Twitter that Sessions "should clarify his testimony and recuse himself." Republican Senator Rob Portman echoed this, saying, "I think it would be best for him and for the country to recuse himself from the DOJ (Department of Justice) Russia probe."

However, Republican House Speaker Paul Ryan told reporters he saw no purpose in Sessions recusing himself unless the attorney general himself was the subject of an investigation. US Senator Richard Burr, the Republican chairman of the committee responsible for investigating allegations of Russian election meddling, said in a statement he trusted Sessions to decide if he should be involved in the probe.

Trump fired his national security adviser, Michael Flynn, in February after it emerged that the retired lieutenant general had discussed US sanctions on Russia with Kislyak before Trump's swearing-in on January 20, and then misled Vice President Mike Pence about the conversations.

Trump called frequently during his campaign for improved relations with Russia, drawing criticism from Democrats and some Republicans given that ties have been deeply strained in recent years over Moscow's military interference in Ukraine, military support for President Bashar al-Assad in Syria and President Vladimir Putin's intolerance of political dissent.

'FALSE' ALLEGATION

In a statement late on Wednesday, Sessions said he had never discussed campaign details with any Russian officials. "I have no idea what this allegation is about. It is false," he said.

Sarah Isgur Flores, a Sessions spokeswoman, said Sessions had more than 25 conversations with foreign ambassadors in 2016. "There was absolutely nothing misleading about his answer," she said in a statement. "He was asked during the hearing about communications between Russia and the Trump campaign - not about meetings he took as a senator and a member of the Armed Services Committee."

Sessions has resisted calls to recuse himself from the investigations. He told NBC News on Thursday morning, "Whenever it's appropriate I will recuse myself, there's no doubt about that."

"I have not met with any Russians at any time to discuss any political campaign," he added.

The White House dismissed the revelation of the meetings as a partisan attack, saying Sessions' contacts with the ambassador had been as a member of the Armed Services Committee. The Russian Embassy to the United States, shrugging off the uproar, said on Thursday it was in regular contact with "US partners."

Before Trump took office, US intelligence agencies concluded that Russia had sought to influence the election campaign, including by hacking into and leaking Democratic emails. The Kremlin has denied the allegations.

During Sessions' confirmation hearing, Franken asked him what he would do if he learned of any evidence that anyone affiliated with the Trump campaign communicated with the Russian government in the course of the campaign. Sessions said he was not aware of any such activities, adding, "I have been called a surrogate at a time or two in that campaign and I did not have communications with the Russians."

On Thursday, Franken told CNN of the Sessions testimony: "At the very least, this was extremely misleading. He made a bald statement that during the (election) campaign he had not met with the Russians. That's not true."

Asked by Democrat Patrick Leahy in a confirmation questionnaire whether he had been in contact with "anyone connected to any part of the Russian government about the 2016 election, either before or after Election Day," Sessions responded, "No."