"We'd love to see a negotiated settlement to this war that is permanent, enduring and fair. And that's what we're committed to continuing to do," Rubio told reporters during a visit to Portugal.
US President Donald Trump's administration in recent weeks has sought to revive talks to end the four-year-old conflict, with Ukrainian negotiators set to visit the US for talks on Friday and Saturday.
Mutual drone attacks by Russia and Ukraine this year have gradually spread across the economy, hitting targets from energy facilities and refineries to ports and vessels carrying oil and grain, e-commerce warehouses and, most recently, data centres.
Russian technology and AI company Yandex said on Thursday it could not yet determine whether equipment at a data centre hit by a Ukrainian drone attack could be restored.
Yandex said earlier that the attack on its Sasovo hub, one of its five large data centres, caused a fire and forced it to suspend operations at the site, which hosts tens of thousands of servers.
"The scale of the damage to the infrastructure is still being assessed," Yandex said in a statement.
"For the moment, we cannot confirm whether it is possible to restore the data centre equipment in Sasovo."
The company earlier said some of its services were unavailable and specialist teams were at the site assessing the damage.
Two of Yandex's three supercomputers, used to develop its AI model, are housed at the Sasovo data centre.
Yandex has not said whether they were damaged.
Rubio said on Thursday escalations could spark a wider conflict.
"That escalation could wind up being a sabotage campaign in neighbouring countries that are members of NATO," Rubio said, adding that other things "could quickly turn what is a war between two countries into a much broader and far more dangerous regional conflict".
"This war needs to end in a negotiated settlement. The sooner, the better. The United States stands ready to facilitate that. We have tried. We will continue to try. But we're also not going to invest in pointless processes if we can't make progress," Rubio added.
US envoys Steve Witkoff and Jared Kushner will meet Ukrainian representatives on Friday in Miami to discuss new ideas and try to produce a unified proposal for resolving the war, a US source familiar with the plan said on Thursday.
The source said Witkoff and Kushner would hold a working session with the Ukrainians to discuss "new ideas and proposals that American negotiators began developing with the Russians and Ukrainians during their recent visit to the region".
The meeting will include representatives from the White House National Security Council and US Treasury Department, the source said.
Ukraine's chief of staff Kyrylo Budanov, intelligence chief Rustem Umerov, and top negotiator David Arakhamia will represent Ukraine.
The US negotiators also invited national security advisors from the United Kingdom, France and Germany as well as officials from NATO and the European Union.
They are expected to discuss proposals for security guarantees for Ukraine, a post-war prosperity plan and other aspects of the conflict, the source said.
The source said the Europeans had told the United States of their frustration with high energy costs and other major financial effects of the conflict.
"It will be a tough winter if the war does not stop. So, the United States is trying to mediate with the sides with the goal of creating a unified proposal," the source said.
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