Washington, Nov 4 (IANS): The trial of Paul Manafort, who served as US President Donald Trump's campaign chairman, may begin in May 2018, a federal judge has announced.

Judge Amy Berman Jackson's proposal for a May 7, 2018, start date comes as Manafort's attorneys said on Friday that they planned to challenge the legal basis of the charges against him, as well as evidence was "improperly obtained" by search warrant and subpoena, reports CNN.

The attorneys could attempt to change the trial date during a court appearance on Monday, Jackson said, if they believe it was too early to set a date or they have scheduling conflicts.

However, Jackson made clear she would not allow changes to a trial date once it was finalized.

Currently, Manafort and Trump's longtime business partner and campaign deputy, Rick Gates are under house arrest on charges brought by the special counsel investigating alleged Russian interference in the 2016 US presidential election.

Both men are barred from leaving their homes for any reason other than court appearances, meetings with attorneys, medical appointments or religious activities.

Facing a dozen charges that include money laundering and conspiracy, both entered pleas of being not guilty, CNN reported.

Justice Department Special Counsel Robert Mueller said on Friday that should Manafort and Gates go to trial, prosecutors would need three weeks to present their case.

Investigators had been targeting Manafort, who worked as a lobbyist, for months and the FBI searched his house in July.

Manafort once worked for Russian oligarch Oleg Deripaska - who says the American owes him $18 million - and was involved in questionable business deals with pro-Russian elements in Ukraine.