Vladimir Putin is ready to issue a "response" of "military-political consequences" should the UK supply planes to Ukraine to help in their war against Russia.
On Wednesday, President Zelensky visited London for the first time since Russian forces invaded Ukraine last year, giving thanks to Britain for their continued support since the start of the fight against Russia.
Prime Minister Rishi Sunak told Zelensky that Britain would help train Ukrainian pilots on advanced Nato fighter jets, saying “nothing is off the table” when it comes to supplying the country with jets to fight Russia.
Peter Nicholls
Later on the Ukrainian President met with French President Emmanuel Macron and German Chancellor Olaf Scholz ahead of a trip to Brussels to lobby European Union leaders for more weapons.
But the Russian embassy to Britain has warned Sunak against sending fighter jets to Ukraine, saying such a move would have ramifications for the entire world.
In a statement cited by Russian state news agencies, the Russian embassy said the "bloodshed, next round of escalation and resulting military and political consequences for the European continent and the entire world.”
The statement continued: "Russia will find a way to respond to any unfriendly steps taken by the British side.”
Zelensky said Sunak had expressed his desire to be able to provide Ukraine with fighter jets, as the PM announced that Britain would start training Ukrainian pilots.
"I heard from Mr Prime Minister the desire to provide fighter jets and officially he declared that they can begin training our pilots," Zelensky said via an interpreter at a joint news conference during the Ukrainian president's visit to Britain.
Having visited London and Paris on Wednesday, Zelensky is expected to attend a summit of EU leaders and address the European Parliament during his trip to the Belgian capital.
Reuters
While Zelensky is unlikely to leave with immediate pledges to satisfy his requests, the visit gives him a chance to press his case in person with all the EU's 27 national leaders for the first time since Russia's invasion nearly one year ago on February 24.
Having won promises of Western battle tanks in recent weeks, Ukrainian officials are now focused on trying to secure the supply of longer-range rockets and fighter jets.
Western governments have so far rebuffed requests for jets, arguing they are not what Ukraine needs for the moment and that it would take years to train Ukrainian pilots to fly them.
A Ukrainian official said Zelensky wanted leaders at the European Council summit to ramp up munitions supplies.
"We need the support of the European Council to speed up arms deliveries to Ukraine," the official said speaking on condition of anonymity.
"We badly need as of now, as of yesterday, long-range artillery, all types of artillery ammunition."
They added: "Battle tanks – the decision has been taken by several member states, but we have no tanks for now. This needs to be speeded up,."