Russia said on Saturday that fighting had been taking place in four regions of Ukraine despite this week's unilateral ceasefire by Moscow, saying its troops had been forced to respond to Ukrainian attacks.

Russia on May 9 paraded combat drones that its forces use in the war in Ukraine on Moscow's Red Square. President Vladimir Putin, Chinese President Xi Jinping and more than two dozen other foreign leaders looked on as various truck-mounted Russian-made drones were driven across the vast square on their launchers,

In the days leading up to the public holiday, Russian cities including Moscow have come under repeated attacks by Ukrainian drones.