Getty ImagesThe US's top diplomat has said he will know "in a matter of weeks, not months" whether Vladimir Putin is serious about peace and a ceasefire in Ukraine.
Speaking after a meeting of Nato foreign ministers in Brussels, US Secretary of State Marco Rubio said ending the war is a decision that will "ultimately" have to be made by the Russian President.
This follows similar comments from his British and French counterparts on Friday morning on the sidelines of the Nato meeting, who also accused Putin of continuing to "drag his feet" and his bombardment.
Meanwhile, Ukrainian authorities said Russian strikes overnight in Kharkiv killed at least five, and a ballistic missile attack later on Kryvyi Rih killed 12.
Russia and Ukraine have ramped up their attacks as US President Donald Trump attempts to bring them together to strike a ceasefire deal to end the more than three years of fighting.
Last month, Ukraine agreed to accept a US proposal for an initial 30-day ceasefire, following talks in Saudi Arabia, while Russia has still to make a decision.
The attack on the northeastern city of Kharkiv came hours before French and British military chiefs arrived in Kyiv to discuss the the possibility of allied troops being deployed to Ukraine in the event of a ceasefire.
In March, allied countries met in the UK to discuss ending the war and defending Ukraine from Russia with a "coalition of the willing".
"There will be at some point a need for military capacity or reassurance, whenever peace is reached," the French Foreign Minister Jean-Noël Barrot, said on Friday.
Talking in Brussels, he was joined by British Foreign Minister David Lammy, who said Putin "could accept a ceasefire now, [but] he continues to bombard Ukraine, its civilian population, its energy supplies.
"We see you, Vladimir Putin, we know what you are doing," he stated, adding that the Russian leader "continues to obfuscate, continues to drag his feet".
When questioned on whether negotiations were a delay tactic, Rubio reiterated Trump's stance on ending the war soon, and said they are "going to wait and see".
"The Russians know our position in terms of wanting to end the war, and we will know from their answers very soon on whether they are serious about proceeding to real peace or whether it's a delay tactic," he added, stressing that Trump was not going to "fall into the trap of endless negotiations about negotiations".
Senior Nato officials have told the BBC that there is no sign Putin is preparing for a ceasefire. Rubio, however, remains hopeful.
"I hope they are. It will be good for the world if the war ended, but obviously we have to test that proposition," he added, explaining that the US would re-evaluate their approach depending on Moscow's response.
"At some point fairly soon - not six months from now - Russia and Putin will have to make a decision."
On Thursday, Poland's Foreign Minister, Radek Sikorski similarly said Putin had weeks not months to show he was serious about ending the war.
"I think if he doesn't agree to a ceasefire, the way Ukraine has agreed to a ceasefire, US patience will not be forever," he said following a meeting he had with Rubio.
He told the BBC he thinks the US is "giving Putin a chance to end the war while saving face", but if he doesn't, it is possible for the "gloves" to come off in the way of more sanctions for Russia and more military assistance for Ukraine.
