UK Prime Minister Sir Keir Starmer has emphasised that international borders cannot be redrawn by military aggression, speaking during high-level diplomatic discussions on the Ukraine conflict.

Starmer’s comments came as he joined US President Donald Trump, Ukrainian President Volodymyr Zelenskyy, and leaders from France, Germany, Italy, Poland, Finland, NATO, and the European Union in a call aimed at advancing negotiations toward a ceasefire in Ukraine.

Starmer underlined that any peace agreement must include strong, credible security guarantees for Ukraine, highlighting Britain’s commitment to the country’s territorial integrity. President Trump’s recent diplomatic efforts to persuade Russia’s Vladimir Putin to participate in peace negotiations were also praised.

Participants on the call agreed that the coming days would be decisive for Ukraine’s future. They also pledged ongoing co-operation toward achieving a “fair, sustainable settlement”.