US President Donald Trump retains private attorney Marc Kasowitz to protect him in Russia inquiry

This file handout photo taken on May 10, 2017 made available by the Russian Foreign Ministry shows US President Donald Trump (C) speaking with Russian Foreign Minister Sergei Lavrov (L) and Russian Ambassador to the US Sergei Kislyak during a meeting at the White House in Washington, DC.

US President Donald Trump has appointed longtime legal adviser Marc Kasowitz to represent him as a private attorney on matters related to the investigation into his election campaign's alleged ties to Russia.

The decision to retain Kasowitz, who has represented Trump on a "wide range of litigation matters for over 15 years," comes as the FBI and multiple congressional committees are looking into the Trump campaign's possible contact with Russians.

The appointment of a private attorney may signal that Trump is seriously concerned about the impact the federal investigation could have on him personally, especially if others in his administration turn against him.

Legal experts say that it is essential for Trump to have a personal legal team now that a special counsel has been appointed to lead the Russia inquiry.

Kasowitz, a New York-based trial lawyer, is expected to form a team of attorneys to protect Trump, according to Reuters.

File photo of Marc Kasowitz

During 2016 presidential campaign, Kasowitz threatened to take legal action against The New York Times if it did not retract a story about women who accused Trump of sexually abusing them. The newspaper did not withdraw the report.

He also advised Trump in the case of fraud claims against Trump University, a profit education company that ran a real estate training program from 2005 until 2010. After the election, Trump settled the lawsuits for $25 million.

Trump’s problems deepened earlier this month following his abrupt decision to fire FBI Director James Comey amid the investigation into alleged Russian meddling in the election.

Comey has authored a memo that said the president asked him to drop an inquiry about former national security adviser Michael Flynn’s ties to Moscow. Some members of Congress have demanded access to that memo.

White House lawyers have even been researching impeachment procedures as a number of Democrats, accusing Trump of obstruction of justice, have privately indicated they could pursue politically-charged impeachment proceedings.

The latest twist in the controversy came on Tuesday when former CIA Director John Brennan publicly said he had seen intelligence showing members of the Trump campaign had interactions with Russian officials.

Former CIA Director John Brennan testifies before the House Permanent Select Committee on Intelligence on Capitol Hill, May 23, 2017. (Photo by AFP)

"It should be clear to everyone Russia brazenly interfered in our 2016 presidential election process and that they undertook these activities despite our strong protests and explicit warning that they do not do so," he said in testimony before the House Intelligence Committee.

Brennan said he did not know if there had been any intentional “collusion” between Trump associates and the Russian government. “I saw interaction that in my mind raised questions of whether it was collusion.”

However, he said there was a sufficient basis of information and intelligence that warranted further investigation by the FBI to determine "whether US persons were actively colluding."

The US intelligence community concluded in January that Russia tried to influence the presidential election in favor of Trump, including by launching an extensive hacking campaign against senior Democrats.

The Kremlin has categorically denied the allegation. Trump has also rejected the accusations as “baseless” and has called the FBI probe a “witch hunt.”