Former Homeland Security Secretary Jeh Johnson met Monday with Senate Intelligence Committee investigators on the probe into Russia's meddling in the 2016 election.

Johnson arrived on Capitol Hill to meet with the committee this afternoon and spent approximately 90 minutes talking with investigators, a congressional aide told the Washington Examiner.

The former secretary of Homeland Security, who served under President Barack Obama, told reporters he was there to "voluntarily assist the Senate Intel Committee in their work on a very important investigation."

The House Intelligence Committee is also expected to call on Johnson to testify on Russia's interference in the 2016 election.

The Senate panel is ramping up its investigation into potential ties between President Trump's campaign associates and Russian officials.

The committee heard from former FBI Director James Comey on the investigation and his conversations with President Trump last week. Committee members will also hear from Attorney General Jeff Sessions on Tuesday, who offered to appear to respond to several statements Comey made.