Ernst on Russian buildup on Ukraine border: 'We must prepare for the worst'

Sen. Joni ErnstJoni Kay ErnstAlabama GOP gears up for fierce Senate primary clash Biden's court picks face fierce GOP opposition Lawmakers in both parties to launch new push on Violence Against Women Act MORE (R-Iowa) on Sunday called on President BidenJoe BidenBiden says he didn't 'overpromise' Finland PM pledges 'extremely tough' sanctions should Russia invade Ukraine Russia: Nothing less than NATO expansion ban is acceptable MORE to take a tougher stance toward Russia amid its increased military presence along the Ukraine border, inciting concerns of an imminent invasion.

"It's hard to know what Vladimir PutinVladimir Vladimirovich PutinRussia: Nothing less than NATO expansion ban is acceptable Biden huddles with group of senators on Ukraine-Russia tensions US providing Ukraine with additional 0M in military aid amid tensions with Russia MORE is thinking and what his true intentions are, but we do see a very aggressive action on his part, amassing his troops on the Ukrainian border. So we must prepare for the worst, not knowing what those intentions are," Ernst told "Fox News Sunday" host Chris WallaceChristopher (Chris) WallaceWolf Blitzer will host an evening newscast on CNN's streaming service Audie Cornish hired by CNN, will host show and podcast on streaming service The five biggest media stories of 2021 MORE.

"I do think that President Biden needs to be very clear, and very strong and his message to Vladimir Putin," Ernst added, saying she believes President Biden should tell Putin that he will not permit the Nord Stream 2 pipeline to be completed.

Earlier this year, Biden said he would not call for the pipeline to be blocked, saying that it would damage relationships with key European allies.

According to Ernst, there are many U.S. senators who are prepared to move against the pipeline.

"I certainly can't speak for the House, Chris, but I do believe that there is a coalescence around these types of actions in the United States Senate. Democrats are concerned, Republicans are concerned and what we don't want to do is allow President Putin to continue with the pipeline, especially as he is preparing, perhaps, to invade Ukraine," said Ernst.

"So we do have to push back on that and I think that there is a large group of United States Senators that will push back on Vladimir Putin," she added.

Democratic U.S. Sen. Chris MurphyChristopher (Chris) Scott MurphyBiden huddles with group of senators on Ukraine-Russia tensions Overnight Defense & National Security — Texas hostage situation rattles nation Senators to meet with Ukraine president to reaffirm US support MORE (Conn.) appeared to echo some of Ernst's sentiments while appearing on CNN's "State of the Union," though he expressed hope that the upcoming virtual meeting between Biden and Putin will be "fruitful."

"It's up to us in the Congress to make clear that we are going to be diplomatic, political and military partners with Ukraine. We are going to provide them with increased military systems so that they can defend themselves. And I hope that we take steps in Congress in the next week to make that clear," said Murphy.