President Donald Trump has again attacked his Attorney General Jeff Sessions in a rare media conference Monday morning.

When asked about Mr Sessions’ decision to recuse himself from the Russia investigation, President Trump said he was “disappointed” in his one-time staunch supporter.

“I am disappointed in the Attorney General,” he said.

“If he was going to recuse himself he should have told me … and I would have quite simply picked somebody else. I think it is unfair to the presidency.”

When asked if Mr Sessions’ role as Attorney General was safe, President Trump would only say, “we will see what happens”.

“Time will tell. Time will tell,” he added.

His frank assessment of the Attorney General on the White House lawn came just hours after he tweeted that Mr Sessions’ position on the Russian investigation was “VERY weak”.

Attorney General Jeff Sessions has taken a VERY weak position on Hillary Clinton crimes (where are E-mails & DNC server) & Intel leakers!

— Donald J. Trump (@realDonaldTrump) July 25, 2017

Mr Sessions’ recusal means he has no oversight of Special Counsel Robert Mueller, whose wide-ranging investigation has focused on Trump aides and his son-in-law Jared Kushner.

Two people close to Mr Sessions told Reuters the Attorney General, who was the first Republican senator to back the Trump’s presidential campaign, has been deeply offended by the public berating from his boss, but his resolve to stay is strong.

The criticism of Mr Sessions comes as a US Senate panel compelled President Trump’s former campaign manager Paul Manafort to appear at a hearing as part of its probe into alleged Russian meddling in the 2016 presidential election.

The Senate Judiciary Committee’s subpoena summoning Mr Manafort to appear on Wednesday local time was a sign lawmakers are willing to push hard as they probe Russia’s role and potential collusion by the Republican’s campaign.

It also came as President Trump’s son-in-law, Jared Kushner, appeared for a second day before a Senate committee to answer questions about his contacts with Russians during the campaign.

Moscow has denied it worked to influence the election in the Republican candidate’s favour, and Mr Trump has denied his campaign colluded.

Mr Manafort met Senate Intelligence Committee staff on Tuesday morning local time, his spokesman said. But he would not agree to an interview with the Senate Judiciary Committee.

The judiciary panel is looking at a June 2016 meeting in New York with a Russian lawyer organised by Trump’s eldest son, Donald Trump Jr. He released emails earlier this month that showed he welcomed the prospect of receiving damaging information at the meeting about Trump’s Democratic rival, Hillary Clinton.

Negotiations with Mr Manafort would continue, the judiciary panel’s Republican chairman, Charles Grassley told reporters. “If he feels he can come, and he’s willing to negotiate in good faith, there’s other accommodations that can be made for him,” he said.

Lawyers for Trump Jr have been negotiating with the committee about his participation.

Mr Kushner, who is a top aide in Trump’s White House, met Senate Intelligence Committee investigators on Monday, telling reporters afterward he had no part in any Kremlin plot.

He returned to Congress on Tuesday for a meeting with the House of Representatives intelligence panel.

The intense focus on Russia – involving several congressional probes and a separate investigation by a Justice Department-appointed special counsel – has overshadowed President Trump’s legislative agenda as well as his efforts on foreign policy.

Russia is the focus in a bill the House is expected to pass on Tuesday, imposing new sanctions on Russia, Iran and North Korea, potentially hampering Trump’s hopes of pursuing improved relations with Moscow.

The President has called the investigations a politically motivated witch hunt fuelled by Democrats.

The sanctions bill, which has the support of both parties in the House, aims to punish Russia for its 2014 annexation of Crimea from Ukraine and for the alleged election interference.

Trump lashed out on Twitter on Tuesday about “Ukrainian efforts to sabotage” his presidential campaign to aid Clinton. The Ukrainian embassy in Washington denied the accusations.

– With AAP