British Prime Minister Keir Starmer on Saturday urged Russian President Vladimir Putin to sign up to a ceasefire in its war against Ukraine if he is serious about peace, and said allies will keep increasing the pressure on the Kremlin,

Russian President Vladimir Putin’s response to a US-proposed ceasefire in Ukraine is “not good enough,” Britain’s Prime Minister Keir Starmer said, after hosting a virtual summit aimed at drumming up support for Kyiv and piling pressure on Russia.

The remarks by the Russian leader suggested he wanted to draw out negotiations or make a truce impossible. Ukraine’s leader called the response to a cease-fire plan “manipulative.”