Two Senate Democrats say Attorney General Jeff Sessions should resign if it turns out he lied about a reported third meeting with Russian Ambassador Sergei Kislyak during the presidential campaign.

"We served with the Attorney General in the Senate and on the Judiciary Committee for many years," Sens. Pat Leahy, D-Vt., and Al Franken, D-Minn., said in a joint statement Thursday. "We know he would not tolerate dishonesty if he were in our shoes."

"If it is determined that the Attorney General still has not been truthful with Congress and the American people about his contacts with Russian officials during the campaign, he needs to resign," they said.

Leahy and Franken revealed that they asked then-FBI Director James Comey on two separate occasions to investigate the possibility that Attorney General Jeff Sessions may have had an unreported third meeting with Kislyak.

During his confirmation hearing, Sessions said he had no contacts with Russian officials in 2016, but it was later revealed he met with Kislyak twice. Sessions said later that the question was whether he had contact with Russian officials in the context of the campaign, and said his two meetings with Kislyak were incidental, and a natural part of his daily work as a senator.

The two senators wrote letters in March and in April asking Comey to direct the FBI to investigate the possibility of a third meeting, but Comey was abruptly fired by President Trump on May 9.

"Earlier this year, Attorney General Sessions provided false testimony before the Senate Judiciary Committee in response to our questions regarding his contacts with Russian officials," they wrote. "[W]e remained concerned that he had still not been forthcoming about the extent of his contacts with Russian officials."

A CNN report late Wednesday said congressional investigators are now looking into whether Sessions had an unreported third meeting with Kislyak.