A Russian missile attack on the Ukrainian city of Sumy, which killed 34 people - including two children - and injured 117 others, has been strongly condemned by Kyiv's Western allies, BBC reported.

Two ballistic missiles struck the city centre mid-morning on Sunday, exploding near the state university and congress centre, leaving bloodied bodies scattered in the streets.

US Secretary of State Marco Rubio called the attack "horrifying" while Germany's chancellor-in-waiting, Friedrich Merz, accused Russia of committing a war crime.

There was no immediate official comment on the attack from Russia, whose forces across the nearby border are said to be preparing for a major offensive, according to BBC.