Two Russian ballistic missiles slammed into the heart of the northern Ukrainian city of Sumy on Sunday (April 13), killing 35 people and wounding 117 in the deadliest strike on Ukraine this year, officials said.

A video livestream of a church service being held in the city captured the moment the two strikes hit with the sound of deafening explosions shaking the whole church building.

Reuters was able to independently verify the location by the position, windows and interior design of the church which matched file and satellite imagery of the area.

President Volodymyr Zelenskiy demanded a tough international response against Moscow over the attack, which came with U.S. President Donald Trump's push to rapidly end the war struggling to make a breakthrough.

Moscow said on Sunday it had hit a meeting of Ukrainian officers with "Western colleagues" in Sumy, but did not identify any Western participants or provide evidence to support the allegation.

The leaders of Britain, Germany and Italy condemned the attack. Trump, when asked about the Russian strike, said that it was terrible.

Sumy, with a population of around a quarter of a million and located just over 25 km (15 miles) from the Russian border, became a garrison city when Kyiv's forces launched an incursion into Russia in August.

Sumy's acting mayor, Artem Kobzar, announced three days of mourning for the victims starting from Monday.

(Production: Vitalii Yalahuzian, Monica Naime, Natasha Montague)