A top Kremlin official and ally of Vladimir Putin has called president Volodymyr Zelensky a “bastard”, “halfwit” and a “c--t” over plans for a peace conference in Switzerland.

Dmitry Medvedev’s expletive-laden rant comes after Mr Zelensky has repeatedly insisted that Russia is not invited to a proposed June “peace summit” in Switzerland as there is no assurance that Moscow will bargain in good faith. Mr Medvedev is Russia’s former president, put in power as a puppet for Mr Putin.

Mr Medvedev’s comments echoed Dmitry Peskov, a Kremlin spokesman, who said on Thursday that the June gathering would not be a “serious conference with serious expectations of some kind of results” without Russia’s presence.

Despite Kyiv’s reservations, the country’s deputy intelligence chief has warned that Ukraine will at some point have to enter into direct talks with Russia to bring the war to an end.

Vadym Skibitsky, deputy chief of Ukraine’s HUR military intelligence service, told the Economist that such wars can only end with treaties, adding that both sides are currently jockeying for “the most favourable position” ahead of potential talks.

Follow the latest updates below.