WASHINGTON    -    A second whistleblower has come forward in the impeachment case against US President Donald Trump, according to lawyers representing the first one.

Mark Zaid told ABC News the second person is also an intelligence official and they have spoken to the inspector general.

The White House has not commented. President Trump has repeatedly rejected the original complaint.

No details have been released about the second whistleblower’s claims.

The Trump impeachment story in short

Who’s who in Trump whistleblower story?

However, Mr Zaid said they have first-hand knowledge of allegations associated with the phone call Mr Trump made with Ukrainian President Volodymyr Zelensky on 25 July.

The impeachment inquiry stems from the call, which was flagged up by the initial whistleblower in August. On Friday, the New York Times reported that a second person was considering coming forward and they had “more direct information” about the events surrounding the call. It is not yet known if this is the person represented by Mr Zaid.

Four quick questions on Trump-Ukraine

Why is Mr Trump being investigated? A whistleblower alleges he used “the power of his office to solicit interference from a foreign country in the US 2020 election”, by asking Ukraine to investigate his main rival, Joe Biden.

Is this illegal? If this is what he’s proven to have done, then yes: it’s illegal to ask foreign entities for help winning a US election. Mr Trump says it’s a witch-hunt and he did nothing wrong.

What could happen next?

If the Democrat-controlled House of Representatives voted to impeach Mr Trump, there’d be a trial in the Senate.

Could he be removed?

A Senate vote needs a two-thirds majority to convict, but Mr Trump’s Republican party controls the Senate so that’s unlikely. And the Mueller inquiry made clear you can’t charge a sitting president with a crime.