The British Prime Minister Keir Starmer and France's President Emmanuel Macron urged on Thursday to increase the pressure on Russia.
The two leaders also announced that they have a long-term plan for when a possible ceasefire is reached – which includes a "peacekeeping force".
"We have a plan that is ready to be initiated hours after a ceasefire", said Macron.
To secure a ceasefire, they want to see new sanctions against Moscow.
"To achieve peace, we must force Putin to the table. A coordinated pressure will make a difference", said Starmer.
Macron, who also urged to "increase the pressure on Russia", added that "we clearly need something new. Something that can affect the pressure on the Russian economy".
What sanctions they are referring to is not disclosed.
The two leaders made the appeal in a video meeting with other countries in the "coalition of the willing" – about 30 Western countries that have committed to deeper support for Ukraine.