Dec. 19 (UPI) -- U.S. Secretary of State Marco Rubio said Friday that U.S. negotiators have made "progress" attempting to end the war between Russia and Ukraine, but ultimately "it's not our war."

The Russian invasion of Ukraine was one of several global issues Rubio addressed during his 2-hour year-end news conference with reporters. He said despite the progress in negotiations, "we have a ways to go" to end the nearly four-year war in eastern Europe.

"And obviously, the hardest issues are always the last issues," he said during the briefing.

"Maybe that happens this week, maybe that happens next month, maybe that's not ready for a few months," Rubio said of a deal.

His comments came ahead of a weekend meeting in Miami between U.S. and Russian negotiators. He said that while the United States is trying to work on a deal that would make both parties happy, he's not willing to force a plan.