WATCH: Dem pursuing GOP backers for vote on Russia inquiry

A key House Democrat says he's contacting Republican lawmakers needed to force a vote on a bill that would create an outside, independent inquiry into Russian interference in the 2016 presidential election.

"Just by the numbers we need 21 Republicans to join us," Rep. Eric Swalwell (D-Calif.) said in an interview with The Hill's Molly K. Hooper

Swalwell, a co-sponsor of the Protecting Our Democracy Act, noted he needs 218 signatures on the discharge petition to force a House vote on his bill.

To date, only two Republicans — Reps Justin Amash (Mich.) and Walter Jones (N.C.) — have signed the discharge petition, though Swalwell revealed that he met privately with another GOP colleague Wednesday morning and is continuing his outreach.

Swalwell noted that President Trump's recent firing of FBI Director James Comey, as well as subsequent reports that the president leaked classified information to Russian officials during a meeting last week, have prompted some GOP lawmakers to call for independent inquiries.

"The Republicans are concerned but I need to get them to the point where their concern is pen on paper, signing the petition," Swalwell said, adding that he introduced his bill in December and "the bridge is still open."

Watch the video above to hear Swalwell in his own words.