Whether Russia is “serious” about achieving a ceasefire in Ukraine should become apparent in a “matter of weeks,” Secretary of State Macro Rubio told reporters Friday.

“The Russians know our position in terms of wanting to end the war, and we will know from their answers very soon whether they are serious about proceeding with real peace or whether it is a delay tactic,” Rubio said at NATO headquarters in Brussels. 

Questions are mounting over Moscow’s true interest in engaging with the Trump administration after it rejected a 30-day ceasefire proposed by Ukraine in early March, then refused to agree to a Black Sea ceasefire later that month unless sanctions were lifted.

President Donald Trump meets with Russian President Vladimir Putin on the first day of the G20 summit in Osaka, Japan, June 28, 2019. (Kremlin Press Office/Handout/Anadolu Agency/Getty Images)

“I guess it’s part of the game,” Rubio said. “At the end of the day, what’s going to matter here is whether we’re going to move towards peace or not.”

Rubio reiterated that Ukraine and Russia would both need to make concessions to end the war but declined to say what those should be, insisting those details should emerge through negotiations.

“Initially, it was important to talk [to the Russians] because we haven’t talked to them in a long time. But now we’ve reached the stage [where] we need to make progress,” he said, noting it will be “hard,” but he remains “optimistic.”

“There are some promising signs. There are some troubling signs. It’s not going to be easy. No one ever said this would be easy, but we’re going to find out sooner rather than later,” Rubio told reporters. “And let’s just say I’m hopeful. I remain hopeful.”