Donald Trump's former lawyer Rudy Giuliani is in talks with the US Congress to testify about his role in last year's attack on the Capitol, according to reports.

       Sources told The New York Times that Mr Giuliani is negotiating with the House of Representatives committee investigating the 6 January riot and may answer some of its questions.

       The committee, which comprises seven Democrats and two Republicans, has issued a subpoena seeking to legally compel Mr Giuliani to testify about his wide-ranging campaign to overturn the result of the 2020 election.

       Mr Giuliani, a former mayor of New York City and Republican presidential candidate, played a leading role in Mr Trump's attempt to negate his defeat with dubious claims of widespread voting fraud.

       His efforts led the state of New York and the city of Washington, DC to ban him from practising law, with a New York court accusing him of making “demonstrably false and misleading statements”.

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       According to the New York Times, the committee's subpoena orders Mr Giuliani to hand over all documents relating to the Trump team's pressuring of state election officials, its contacts with congressfolk, its plans to potentially seizing voting machines, and Mr Giuliani's fees as a lawyer.

       Sources told ABC News that the negotiations were nowhere near final and could yet collapse, with Mr Guiliani reluctant to share any of his communications with Mr Trump.

       A spokesperson for the committee said: "Mr Giuliani's appearance was rescheduled at his request. He remains under subpoena and the select committee expects him to cooperate fully."

       Most of Mr Trump's closest allies have refused to testify before the committee, which is has interviewed more than 500 people as it probes Mr Trump and his aides' role in the violence at the Capitol.

       Last year the committee charged Mr Trump's former chief of staff Mark Meadows and onetime adviser Steve Bannon with criminal contempt, although Mr Meadows did hand over some documents.

       Sources told the Times that Mr Giuiliani's lawyer has signalled to the committee that he will be less rigid, but was still negotiating over whether to give a formal deposition or an informal interview.