Vice President Mike Pence said the Trump administration is “very troubled by the increased hostilities over the past week in eastern Ukraine,” but suggested the future of sanctions against Russia would ultimately hinge “on how the Russians respond in the days ahead.”

At least 33 people were killed last week in a surge of violence between Russia-backed rebels and government forces in eastern Ukraine. Amid concerns that President Donald Trump could undo U.S. sanctions against Russia, ABC’s George Stephanopoulos asked Pence whether sanctions would remain in place as long as Russia is violating the ceasefire in Ukraine. “It just simply all depends,” Pence replied.

Pressed to clarify what, exactly, continued sanctions would depend on, Pence replied, “On whether or not ― we see the kind of changes in posture by Russia. And the opportunity, perhaps, to work on common interests. And the president’s made it clear the top priority of this administration is to hunt down and destroy ISIS at its source.”

“If we have opportunities to work together ― I think the president is looking for an opportunity to begin that relationship anew,” Pence added. “But ― make no mistake about it ― those decisions will await action.”

Former President Barack Obama sanctioned Russia in 2014 over Moscow’s annexation of Crimea. Prior to leaving office, Obama announced additional sanctions over reports of Russian government interference in the U.S. elections.

Yet even prior to his presidential victory, Trump made overtures toward Russia and its president, Vladimir Putin, for whom sanctions relief is a huge priority. In a recent Fox News interview, Trump brushed off host Bill O’Reilly’s description of Putin as a “killer” by saying, “There are a lot of killers.”

In a separate interview on Sunday, Pence defended Trump’s remarks about the Russian president, telling NBC, “The president has said many times if we got along with Russia better, that would be a good thing for the world. If we were to able to work with Russia to hunt down and destroy ISIS and confront radical Islamic terrorism, that would be a good thing.”

However, the vice president took a harder line on Iran, which the U.S. sanctioned last week over a missile test.

“Iran would do well to look at the calendar and realize there’s a new president in the Oval Office,” Pence told ABC. “And Iran would do well not to test the resolve of this new president.”