United States Attorney General William Barr on Monday confirmed that the US Department of Justice has received information from President Donald Trump's personal lawyer Rudy Giuliani ahead of the November election, but cautioned that any information originating from Ukraine should not be taken "at face value".

Barr spoke at a news conference a day after Republican Senate Judiciary Committee Chairman Lindsey Graham said on the CBS News programme Face the Nation that the department had created a process so that Giuliani could provide information and the department would see if it could be verified.

The Justice Department would not say whether new information from Giuliani meant an investigation had been opened into Democratic presidential candidate Joe Biden and his son Hunter.

More:

Barr said accepting information from Giuliani was part of a larger Justice Department "intake process in the field" that will be used to assess the "provenance and credibility" of any information about the candidates running in November's presidential election.

"We have to be very careful with respect to any information coming from the Ukraine," Barr told reporters on Monday. "There are a lot of agendas in the Ukraine. There are a lot of crosscurrents, and we can't take anything we receive from the Ukraine at face value".

"That is true for all information that comes to the department relating to the Ukraine, including anything Mr. Giuliani might provide," he added.

Democratic impeachment investigators allege Trump attempted to pressure Ukraine into investigating the Bidens for his own political gain, while Republicans have said the Bidens' involvement in the country warranted legitimate probing. To date, there is no evidence of wrongdoing by the Bidens.

Giuliani, the former mayor of New York City, loomed large over the impeachment investigation and trial. As an unofficial envoy to Ukraine, he faced criticism from those who said his role often blurred the lines of unofficial and official government business as he pushed for the investigations into the Bidens.

Since the inquiry began, Giuliani has publicly touted his own investigation into the Bidens' involvement with Ukraine in an attempt to vindicate the president.

The Senate, voting mostly along party lines, acquitted Trump last week on impeachment charges that he had abused his power in pushing for the investigations and then obstructed Congress by prohibiting his administration from cooperating in the investigation.

Awkward position

Giuliani is himself also under scrutiny by federal authorities, meaning the Justice Department could be putting itself in the awkward position of appearing to work with someone it is actively investigating to gather potentially damaging information against one of the president's political rivals.

Federal prosecutors in New York are investigating Giuliani's business dealings, including whether he failed to register as a foreign agent, according to people familiar with the matter.

Although the department acknowledged it is receiving and scrutinising material from Giuliani, the FBI's number two official would not say if that meant a formal investigation into the Bidens had been launched.

"I am not going to talk about any investigations as I never would. We do not talk about open investigations," FBI Deputy Director David Bowdich also said on Monday.