Ukrainian negotiators traveled to the US on Friday and Saturday in an effort to urge US President Donald Trump to increase sanction pressure on Russia.
Ukrainian officials believe that Russia is unlikely to end the war full stop and think that a partial ceasefire, which has been floated before, seems like the most realistic option.
Rubio said that it was a challenge to find an "end that both sides can accept," but that the US is "prepared to play that role in a positive way."
"Yesterday... not a single ship entered the port," Zelensky told reporters on Thursday. "They've been hitting all the ships. They're going to step this up."
Ukraine has become increasingly proficient in using tens of thousands of drones a week in its war with Russia.
Oleksandr Syrskyi said Ukraine is on the offensive while also holding the defensive line against Russia, as he prepares to hand command of the army to young general Mykhailo Drapatyi.
The breaches have resulted in the violation of the air sovereignty of 12 countries, repeatedly forcing the closure of major airports and disrupting military activity.
The change follows days of street protests sparked by a surprise governmental reshuffle that ousted the popular defense minister.
Donald Tusk said that Russia holds a rigid stance, making it unlikely for the Ukraine-Russia War to end soon, while Poland prepares to ensure the security of Ukraine in the event of a ceasefire.
Russia says it only attacks targets of military relevance and denies targeting civilians.
The Elysee said that planning was still underway for security guarantees for when a ceasefire is reached between Ukraine and Russia.