The former President of Ukraine has called for a resource from the West that could be a "game-changer" in its war efforts against Ukraine.
It comes as Rishi Sunak reportedly discussed efforts to "accelerate military support" to Ukraine in a call with Voldomyr Zelensky.
The Prime Minister is also said to have called on those responsible for the beheading of a Ukrainian soldier to be held to account.
Speaking on GB News, the ex-Ukrainian President Petro Poroshenko has called for the introduction of F-16 fighter jets into the supply from Britain.
He told Mark Longhurst: "Zelensky wants Sunak to deliver us the F-16s. These are the fighters that can stop the Russian dominance in Ukrainian skies.
"We can get a more successful Ukrainian operation. We are hearing that these F-16s could be a game changer and will be an important factor for our future defence."
After a video of a Ukrainian soldier being beheaded by Russian troops surfaced, the ex-President hit out at Vladimir Putin, saying he is responsible for "mass genocide".
In a fiery statement on GB News, he said: "This video proves the latest Russian atrocities in Ukraine. This is one of thousands of disasters that have happened in Ukraine during the last year.
"I was among the first who came to see with my own eyes how the streets were full of dead people without heads, and without hands.
"This is has only one name - genocide. I want to call out to all our partners across the International Community - Putin, his circle, the leadership of his army and the executor of these disasters should be held responsible in an international court. We should never let it repeat again."
His comments come days after a gruesome video appearing to show a Ukrainian captive being beheaded by a Russian soldier was condemned by Volodymyr Zelensky,
The clip appears to show a man in green fatigues wearing the yellow armband typically used by Ukrainian soldiers. He is heard screaming before another man apparently uses a knife to decapitate him.
It appears to have been taken by one of the apparent Russian soldiers.
"There is something that no one in the world can ignore: how easily these beasts kill," the Ukrainian president later said. "There will be legal responsibility for everything. The defeat of terror is necessary," he added in a video message.
Ukraine's foreign ministry called on the International Criminal Court to "immediately investigate yet another atrocity of the Russian military".
The UN said it was "appalled" by the footage.