US President Donald Trump tried on Friday to turn the tables on Democrats by linking them with Russia, at the same time his Attorney General Jeff Sessions remained under investigation for his contacts with Moscow.

On his personal Twitter account, Trump urged an immediate investigation of Senate Democratic minority leader Chuck Schumer's connections with Russia and Kremlin boss Vladimir Putin, EFE news reported.

In his tweet, Trump made the request and posted a photo of Putin together with Schumer, calling the New York Senator a "total hypocrite".

The photo in question is from September 2003 and was taken in New York at the first gas station in that city belonging to Russia's Lukoil company.

The Senator replied to the President, also on Twitter, almost immediately and told him he had no problem talking about his contact with Putin and the Russian leader's associates, which "took place in 2003 in full view of press & public under oath", and challenged Trump to say whether "you & your team" would do the same about their contacts and connections with Russian officials.

Trump called for an investigation of Schumer as the scandal boiled over about Russia's contacts with Sessions, whose position is the equivalent of the Justice Minister in other countries.

While he was Senator and Advisor to Trump's electoral campaign, Sessions met twice with the Russian ambassador in Washington, Sergey Kislyak, in the months preceding last November's US presidential election and amid evidence of Moscow's interference in the election.

While the Senate was in the process of confirming Sessions as the new Attorney General and asked about his contacts with the Kremlin, he decided to hide his meetings with Kislyak because, he now says, they were associated with his position as Senator and not as an Advisor to the Trump campaign.

But under the unrelenting criticism, Sessions gave a press conference this Thursday to announce he would not take part in the investigation by his department, the Department of Justice, into the suspected Russian hacking into the presidential elections to harm the chances of Democratic candidate Hillary Clinton, EFE news reported.

In a statement to reporters, Sessions said, "I have decided to recuse myself from any existing or future investigations of any matters related in any way to the campaigns for President of the United States." 

During a breakfast organised by the digital daily Politico, the leader of the Democratic minority in the House of Representatives, Nancy Pelosi, called "insufficient" and "totally unacceptable" Sessions' decision to recuse himself.

In Pelosi's opinion, the fact that Sessions decided to exit the investigations is "an admission" that he knew he did wrong in hiding from the Senate his contacts with the Russian ambassador, and was "a reflection of the weak moral authority of this administration."

After noting his "total confidence" in Sessions, Trump said on Thursday in another tweet that his Attorney General "could have stated his response more accurately" when asked about Russia in the Senate, but it was unintended and he did nothing wrong.