Russia bombed a children’s hospital on Monday while its negotiators met with a US delegation to discuss steps towards a possible ceasefire.

At least 17 children were among 88 injured in the missile strike on a residential area in the city of Sumy, which coincided with the second round of US-led ceasefire negotiations in Riyadh.

Andrii Sybiha, Ukraine’s foreign minister, said Russia “must stop bombing our cities and end its war on civilians” instead of making “hollow statements about peace”.

The talks in Riyadh were expected to focus not on an overall ceasefire, but more narrow agreements on a suspension of attacks on energy infrastructure and safe passage for vessels in the Black Sea.

Hours before a US team met with Russia’s negotiators, Ukraine destroyed four Russian helicopters using US-made Himars missiles in a strike behind enemy lines made possible through US-supplied intelligence.

Vladimir Putin has said the key condition for a 30-day ceasefire was an end to deliveries of Western weapons and intelligence to Kyiv. Donald Trump cut off supplies in February in an effort to bring Ukraine to the negotiating table, but they have since restarted.