In this image from video released by the House Select Committee, Vice President Mike Pence looks at a phone rom his secure evacuation location on Jan. 6 that is displayed as House select committee investigating the Jan. 6 attack on the U.S. Capitol holds a hearing Thursday, June 16, 2022, on Capitol Hill in Washington.

House Select Committee | AP

Former Vice President Mike Pence was issued a subpoena by the special counsel investigating ex-President Donald Trump for his efforts to overturn his 2020 election loss and events leading to the Jan. 6 Capitol riot, NBC News confirmed Thursday evening.

Pence, who served under Trump, was pressured by him to refuse to accept the certifications of the Electoral College slates of several states that gave President Joe Biden his margin of victory in that race.

Pence did not agree with Trump’s request when he presided over a joint session of Congress that confirmed Biden’s victory.

That joint session on Jan. 6, 2021, was interrupted for hours by a mob of Trump supporters who stormed the U.S. Capitol, sending Pence and members of Congress fleeing to hide from the invaders. Trump refused for hours to act on requests that he publicly call on his supporters to leave the Capitol.

ABC News first reported that special counsel Jack Smith had subpoenaed Pence. ABC also reported that the subpoena was issued after months of negotiations between federal prosecutors and Pence’s legal team.

It was not clear whether Smith is seeking Pence’s testimony, documents, or both.

Spokesmen for both Pence and Smith declined to comment on the subpoena.

Smith previously issued a subpoena seeking documents from Georgia Secretary of State Brad Raffensperger, whom Trump had pressured in early 2021 to “find” him enough votes in that state to overcome his ballot deficit to Biden there.

NBC reported in December that officials in swing states received subpoenas from Smith for communications involving Trump, his campaign, and aides and allies who were involved in the attempts to overturn Biden’s victory.

Smith is also investigating Trump for removing White House documents, many of which were classified, and shipping them to his Mar-a-Lago club in Palm Beach, Florida, where he has lived since leaving office.

Smith was appointed special counsel by Attorney General Merrick Garland after Trump declared his candidacy for the 2024 Republican presidential nomination.