Washington (CNN) South Carolina Republican Sen. Lindsey Graham called on President Donald Trump to "go after" Russia due to the threat he said it poses to US elections.

"Russia is going to get worse, if not better," Graham said Sunday. "Mr. President, go after Russia because they're coming after us."

Graham, making his comments on NBC's "Meet the Press," said Trump should hit Russia both for efforts in 2016 to influence the US presidential election and threats it might pose in the immediate future.

Earlier this year, Congress overwhelmingly passed a bill, which Trump signed into law , that included restrictions on him unilaterally removing sanctions on Russia and pushing him to increase them on several fronts.

However, the administration missed an October 1 deadline in the bill to put new sanctions in place, drawing ire from some in Congress who want the administration to take a harder line.

Graham counted himself among them on Sunday, saying the Trump administration is "slow" on Russia.

"They have a blind spot on Russia; I still can't figure out," Graham said.

During the campaign and since taking office, Trump has called for the US to seek a better relationship with Russia and has openly doubted the conclusion of the US intelligence community that Russia was behind efforts to disrupt the 2016 election and boost his presidential campaign.

Several congressional investigations and an executive branch investigation led by former FBI Director Robert Mueller continue to examine Russian influence in the 2016 election and allegations of coordination with Russia by Trump's associates.

Graham said he believed Russia interfered in the 2016 race but did not affect the outcome. However, he warned Russia would attempt to meddle in the 2018 and 2020 elections, and that threat raised a host of unresolved questions.

"What are the rules of engagement?" Graham asked. "Did what they do in 2016, did that amount to an act of war? How do you respond to cyberthreats? We're really not well together as a nation in terms of the threats we're facing from the cyber-arena."