Senate Republicans on Tuesday blocked legislation that would provide funding for states to shore up election security and create more transparency around online advertisements.

Senate Majority Whip John Thune (R-S.D.) blocked passage of the Honest Ads Act, sponsored by Sen. Amy Klobuchar (D-Minn.), saying work was needed to make the measure more bipartisan.

Klobuchar's bill, whose lone GOP co-sponsor is Sen. Lindsey Graham (S.C.), would require online platforms to make "all reasonable efforts" to ensure foreign entities are not buying political ads. It also would require public disclosure of who paid for the ad.

"There are many other bills that I'll come back and discuss in the next few weeks which would help on foreign influence in our elections, but today I want to focus on this one because election security is national security, and it's well past time we take action," Klobuchar said on the Senate floor.

Klobuchar, a White House hopeful, discussed the bill during last week's Democratic debate, urging quick passage in order to guard against foreign election interference.

Senate Minority Whip Dick Durbin (D-Ill.) later came to the floor and attempted to pass the Election Security Act, a measure with 40 Democratic co-sponsors that would give states $1 billion for election security efforts and require backup paper ballots.

Sen. John Kennedy (R-La.) blocked its passage, arguing the bill had "more red flags than the Chinese Embassy." He added that the level of funding was excessive when considering the $380 million appropriated to states last year for election security.

"We had no problems in 2018," Kennedy said, referring to last year's midterm elections. "If I thought for a second that our voting system was in jeopardy, I would be joining with my good friend, the senator. But I'm not much for just spending taxpayer money with a $22 trillion deficit just to be spent."

Kennedy said he intended to introduce an election security bill later on Tuesday that would require the chief election official from each state to report any foreign individuals with access to election machines or election information technology to the Election Assistance Commission.

"If you want to do something to stop foreign nationals from interfering with our elections, we don't need to spend a billion dollars. We need to pass this bill," Kennedy said.

Klobuchar's and Durbin's efforts mark the latest attempt by Senate Democrats to pressure their GOP colleagues to allow votes on election security.

Democrats came to the Senate floor in June and attempted to pass the Election Security Act shortly after former special counsel Robert Mueller testified before the House Intelligence Committee that Russian actors are attempting to interfere in U.S. elections "as we sit here."

Mueller said in his 448-page report that Russian operatives ran a sweeping interference campaign in advance of the 2016 U.S. elections, using both social media disinformation and hacking tactics.

House Democrats have also kept up a sustained effort to push through election security legislation, passing two sweeping bills earlier this year that have stalled in the GOP-controlled Senate.

The House plans to vote on another election security bill - the Strengthening Homeland Security, Intelligence and Essential Law Enforcement Departments Act - on Wednesday.