Ukraine's Western allies including the US are threatening to slap Russia with more sanctions if Moscow fails to sign up to the 30-day truce in Ukraine proposed by the US, CNN reported.US President Donald Trump on Thursday added the threat of additional sanctions from the US and "its partners" to his latest call for an "unconditional ceasefire" between Russia and Ukraine that Moscow has repeatedly rejected,

Russia and Ukraine have both reported attacks on their forces on the first day of a 72-hour ceasefire called by President Vladimir Putin.

Russia on Friday paraded combat drones that its forces use in the war in Ukraine on Moscow's Red Square in what state TV said was a first.

The attacks came a day before a Russian-proposed cease-fire was to take effect and as Moscow prepared to welcome foreign dignitaries for a parade.