Washington, Feb 10 (IANS): A special counsel who is investigating former US President Donald Trump and his role in the January 2021 Capitol riot has issued a subpoena to former Vice President Mike Pence, marking an important milestone in the Department of Justice's (DOJ) two-year probe into the insurrection, an informed source said.

The source told CNN on Thursday that 01:30 special counsel Jack Smith's office is "seeking documents and testimony related to January 6" and want the former Vice President to "testify about his interactions with Trump leading up to the 2020 election and the day of the attack on the Capitol".

The DOJ's probe into the efforts by Trump and allies to impede the transfer of power after he lost the 2020 election, is now being led by special counsel Smith.

Pence is an important witness who has detailed in a memoir some of his interactions with Trump in the weeks after the election.

There has been no official comment on the development either from Pence's office or from the special counsel's.

Months of negotiations preceded the subpoena to the former vice president, CNN reported.

Trump's former acting Department of Homeland Security secretary Chad Wolf had been separately interviewed by DOJ lawyers in recent weeks as part of the ongoing probe.

Instead of appearing before a federal grand jury,Wolf was interviewed under oath by DOJ lawyers and FBI officials.

On January 6, 2021, Trump's supporters stormed the Capitol in Washington, D.C., and disrupted a joint session of Congress to affirm the 2020 presidential election results.

Approximately 140 police officers were assaulted and authorities have linked at least five deaths to the mayhem.

Over 940 individuals have been arrested in nearly all 50 states for crimes related to the breach of the Capitol, including more than 275 individuals charged with assaulting or impeding law enforcement.

Nearly 500 have pleaded guilty.