Even as President Obama signed a Ukraine aid package into law Thursday that also punishes Russia, lawmakers remained skeptical that Russian President Vladimir Putin would be deterred.
"We need to do everything we can to dissuade Putin from being even more expansionary," said Sen. Ron Johnson, who did not specify what stronger steps the U.S. should take but said they should have more "resolve." "Putin only responds to action, he doesn't respond to words. There's a whole host of things we can do to make sure that we change his calculus that if he moves further into Ukraine, there'd be a much higher price to pay across the board."
Johnson, a Wisconsin Republican, was among a number of Senate Foreign Relations Committee members who expressed continued unease Thursday about Putin's ambitions in Ukraine and the surrounding region.
Committee members openly debated whether additional action would be needed after they left a classified briefing on Russia with officials from the departments of State and Defense as well as the Office of the Director of National Intelligence.
After Russia's incursion into Crimea in late February, which resulted in its annexation of the region last month, Congress finally sent a Ukraine aid package to the White House on Tuesday that also seeks to punish Russia by codifying sanctions against Putin's allies.
The panel's ranking member, Republican Bob Corker of Tennessee, said that if Putin continues on the same course, more action could be warranted.
"I think another week of troop buildup on the border and nothing changing, maybe so," he said.
Others argued the key was to keep ratcheting up pressure on Putin through sanctions.
"The sooner we can convince the Europeans to move forward on the next set of economic sanctions, the tighter the noose will be around Putin," said Sen. Chris Murphy, a Connecticut Democrat. "Putin thinks he can negotiate his way into a federal system that will cleave off eastern Ukraine in recognition of their occupation of Crimea. I think we need to move forward on economic sanctions as quickly as possible to make it clear that there will be a continued cost to them if they are not negotiating in good faith."
For his part, committee Chairman Sen. Robert Menendez was tight-lipped about what steps, if any, should be taken next in Congress.
"It remains to be seen," the New Jersey Democrat said. "But we are certainly poised to do more if we have to, if we think it will be a deterrent towards any further Russian aggression."
Menendez added that the Ukraine package Obama signed into law Thursday sends an important message to Russia.
"It's significant because No. 1, not only does it codify some of the actions that the president took, but it expands upon it," he said. "And clearly some of the consequences of those actions felt by those closest to Putin have been significant. It's like standing in a circle and all of a sudden everyone in the circle is getting a bomb thrown on them and you get the message that it's getting close."
Separately on Thursday, Senate Armed Services Committee ranking member James Inhofe, R-Okla., introduced a resolution to stop further Russian aggression and preserve Moldova's sovereignty, which demands Russia withdraw from the region.