Voldymyr Zelensky has outlined a crucial red line as the US aims to broker a peace deal to end the war between Ukraine and Russia.
The Ukrainian President said he is only prepared to speak to one Russian official, Vladimir Putin.
He said he would only do so once a common plan is negotiated with Donald Trump, whom Zelensky believes is key to a peace deal.
He added that the US President had given him his telephone number.
Zelensky held a meeting with US Vice President JD Vance at the Munich Security Conference on Friday.
He said Ukraine wants “security guarantees” before any talks to end the war.
Trump spoke to Putin over the phone earlier this week, and said the Russian President agreed to enter negotiations.
The US President suggested it is unlikely Ukraine will get all its land back from Russia or be allowed to join NATO.
Zelensky earlier warned the conference that the armies of Europe and Ukraine together “are not comparable” to the size of the Russian army.
He suggested European nations need to increase the size of their forces, echoing similar calls made by the US and NATO Secretary General Mark Rutte.
Both the US and Rutte want to see the alliance spending considerably more.
Latest figures by the International Institute for Strategic Studies think tank show Russia is now spending more on defence than the whole of Europe combined.
The UK currently spends around 2.3% of its GDP on defence, making it one of the 23 nations out of 32 to be achieving the NATO target of 2%.
