Russia must decide whether to sign onto a proposed 30-day ceasefire with Ukraine, a move that could mark a turning point in the war.

"We're going to bring it to them directly. We're going to say that Ukraine is prepared to stop all battlefield activity and begin the immediate process of negotiating and ending of the war," said U.S. Secretary of State Marco Rubio, who helped negotiate the ceasefire proposal "We'll see what the response is. If their response is yes, then we know we've made real progress in and there's a real chance at peace. If their response is no, it would be highly unfortunate and it would make their intentions clear."

Rubio said the proposed pause in fighting would allow all parties to plan the next steps for the region.

RELATED STORY | Kyiv open to ceasefire with Russia as US resumes security aid to Ukraine

"I think we're going to have to be flexible and nimble and creative and patient and work hard at it and hopefully turn it into something that's concrete," Rubio said.

Meanwhile, fighting has intensified in recent days. Ukrainian officials said Wednesday that Russian missile strikes killed at least five civilians. The attacks followed Ukrainian strikes inside Russia.

With a ceasefire on the table, the U.S. has agreed to "lift the pause on intelligence sharing and resume security assistance to Ukraine." The pauses were put in place after a contentious meeting between U.S. President Donald Trump and Ukrainian President Volodymyr Zelenskyy.

RELATED STORY | Trump reflects on meeting with Zelenskyy: 'He very much overplayed his hand'