'Democrats aren't really serious': Devin Nunes threatens to do investigation 'with or without' Dems
House Permanent Select Committee on Intelligence Chairman Devin Nunes (R-CA) speaks to the media about President Donald Trump's allegation that his campaign was the target of wiretaps on Capitol Hill in Washington March 7, 2017. REUTERS/Aaron P. Bernstein

House intelligence committee Chairman Devin Nunes (R-CA) asserted on Wednesday that House Democrats "aren't serious" about an investigation into Russia's interference in the 2016 presidential election.

During an interview with NBC News, Nunes was asked if he was upset that Rep. Walter Jones of North Carolina was the first Republican to call for him to recuse himself from the investigation.

Nunes said no, but added: "We're beginning to figure out who's actually serious about the investigation. Because it appears like the Democrats aren't really serious about the investigation."

Although Nunes has essentially ground the investigation to a halt by canceling all scheduled hearings, the committee chairman placed the blame on obstruction by Democrats.

"They need to give us their witness list because we have no idea who they even want to interview," Nunes insisted. "As far as I know they've done very little to even look through the documents that the intelligence agencies have provided. So, at the end of the day here, we're going to get to the truth, we're going to find out who's actually doing a real investigation."

The chairman also warned that he would proceed without Democrats if they refused to participate.

"At the end of the day, we're going to do an investigation with or without them," he said. "And if they wan't to participate, that's fine."

Democrats have accused Nunes of canceling a recent hearing to shut down the testimony of former acting attorney general Sally Yates, who was expected to contradict statements made by President Trump.