By Ivana Kottasová, Daria Tarasova-Markina and James Frater, CNN

(CNN) — Russia killed dozens of Ukrainian civilians in less than 48 hours on Monday and Tuesday, according to Ukrainian officials, two of the deadliest days in many months.

A five-year-old boy and an 11-year-old girl were among the victims of the Russian attacks, launched just as Ukraine’s allies began gathering for a key NATO meeting in the Netherlands.

Ukrainian officials said 15 people were killed in Dnipro on Tuesday after a Russian ballistic missile hit the city, the largest in the country’s south-east, while 9 people were killed in a strike on a Kyiv apartment building on Monday.

At least two dozen others were killed in strikes across the country, including in Sumy, Kherson, Donetsk and Odesa regions.

In Dnipro, local officials said the missile caused damage unlike any previous attacks on the city.

Mayor Borys Filatov said almost 50 buildings were damaged, including schools, medical facilities, municipal sites and residential buildings.

“This is an unprecedented amount of destruction that the city has never seen before in the entire time of the full-scale war. The number of victims is so high that even ambulances cannot keep up,” he added.

More than 170 people were injured, according to authorities, with around 100 remaining in city hospitals as of Tuesday evening.

A passenger train carrying some 500 people was also damaged in the strike.

“In residential buildings and various municipal facilities throughout the city, we have over 2,000 shattered windows alone,” he said.

Zelensky highlights Russia’s ties to Iran

Ukraine’s President Volodymyr Zelensky was in The Hague for the NATO summit on Tuesday, meeting several European leaders on its sidelines before addressing the Dutch parliament.

Ukraine is not a member of NATO and, while it wants to join, the issue of its potential future membership remains contentious. Russia has tried to prevent Ukraine from ever being able to join the alliance, with Moscow arguing that NATO’s eastward expansion following the end of the Cold War has posed threats to its security.

Zelensky met NATO Secretary General Mark Rutte, President of the European Council Antonia Costa and European Commission President Ursula von der Leyen, all of whom have reiterated their support for Ukraine.

He was hoping to meet US President Donald Trump later on Tuesday, according to Ukrainian officials.

The two were scheduled to meet at the G7 summit in Canada earlier this month, but that meeting did not happen as Trump left the summit earlier than expected because of the Iran-Israel conflict.

As the world turned its attention to the Middle East, Zelensky was keen to highlight the connection between Iran and Russia.

Iran has been among Russia’s strongest backers since President Vladimir Putin launched a full-scale unprovoked invasion of Ukraine in 2022. The Iranian regime has supplied Moscow with weapons, including short-range ballistic missiles and thousands of Shahed drones; according to US officials, it has also built a drone factory in Russia.

Moscow has in turn stood by Iran during the recent conflict with Israel and after the US strikes against Iranian nuclear sites on Sunday.

Russia has intensified its aerial attacks on Ukrainian cities in recent weeks, after successfully scaling up its domestic production of its most frequently used type of drone – the Iran-designed Shahed.

Zelensky said on Tuesday that Russia has launched 28,743 Shahed drones against Ukraine since 2022, with 2,736 fired by so far this month.

“Russia could never have done this without its ties to the Iranian regime,” he said.

The Ukrainian leader told reporters at the summit that there were no signs Putin wanted to stop his war against Ukraine.

“Russia rejects all peace proposals, including those from the United States of America. Putin only thinks about war. That’s a fact. Maybe he connects his own political survival with his ability to keep killing, so long as he kills, he lives,” Zelensky said.

Talks between Russia, Ukraine and third countries have mostly stalled after Moscow refused to back off its maximalist demands and presented a ceasefire proposal that would essentially amount to Ukraine’s capitulation.

Speaking on the sidelines of the summit, British Defense Secretary John Healy said that while “all eyes have been on the Middle East,” it was crucial not to forget about Ukraine.

“Putin wants our focus to slip, and part of the strong message from NATO is that we will not let that happen, and this session is an important part of that,” he said.

Zelensky was in London on Monday, where he met British Prime Minister Keir Starmer as well as King Charles III.

Kyiv officials said the attack on the apartment building on Monday killed multiple members of several families.

Lusy Alekseenkova, a journalist with a Ukrainian TV channel, said her brother, his wife and her sister-in-law’s father were killed in the attack on Kyiv, with her 16-year-old nephew the sole survivor.

The same strike left a mother and her 11-year-old daughter dead, Tymur Tkachenko, the head of Kyiv Military Administration, said on Telegram, adding that it took many hours to recover the little girl’s body.