The foreign ministers of Russia and Ukraine are holding talks in Turkey, as Moscow’s all-out invasion of its neighbour enters its third week.

Ukraine’s Dmytro Kuleba said ahead of the face-to-face meeting with his Russian counterpart Sergei Lavrov that his expectations were “limited”.

It comes after Ukraine accused Russia of bombing a children’s hospital, calling it a “war crime”.

Officials say three people including a child died in the attack in Mariupol.

Seventeen people, including staff and patients, were injured, the local mayor’s office said. Footage shows a building – which also housed a maternity ward – reduced to a shell, with a huge crater nearby.

On Thursday the Kremlin said it would seek information from the Russian military about what had happened.

Meanwhile Ukraine’s deputy prime minister said seven evacuation routes – including routes out of Mariupol and Sumy – would open on Thursday.

Ahead of the talks in Antalya, southern Turkey, Mr Kuleba said: “Frankly… my expectations of the talks are low.”

Ukraine’s foreign ministry said that Kyiv was seeking an immediate “cessation of hostilities and the war against Ukraine by Russia”.

Meanwhile, Russia is demanding that Ukraine abandons its stated plans to join the Nato military alliance, and becomes a neutral-status state. It also says Kyiv must accept Moscow’s jurisdiction over Crimea – the southern Ukrainian peninsula annexed by Russia in 2014.

And Russia is pressing for Kyiv to recognise two self-proclaimed rebel regions in eastern Ukraine.

UN Secretary General António Guterres described the attack as “horrific” and the US accused Russia of a “barbaric use of military force to go after innocent civilians”.

Mariupol – where about 400,000 people live – has been surrounded by Russian forces for several days, and repeated attempts at a ceasefire to allow civilians to leave have broken down.

“The whole city remains without electricity, water, food, whatever and people are dying because of dehydration,” Olena Stokoz of Ukraine’s Red Cross told the BBC on Wednesday.

Western officials – including the White House – have warned Russia could use chemical or biological weapons in Ukraine or create a “false flag” operation – a misleading operation blamed on the other side, usually used to justify a supposed counter-attack.

Moscow earlier said Ukrainian forces had transported some 80 tonnes of ammonia in the country’s north-east, without providing evidence.

Meanwhile US Vice-President Kamala Harris is in Poland, a day after Washington rejected the country’s plan to transfer its jet fleet to the US, rather than directly to Ukraine.

And in Europe, EU leaders are meeting in France’s Palace of Versailles for a two-day summit to discuss Ukraine’s possible future membership, more sanctions on Russia, and a new common defence policy.

US officials estimated that between 5,000 to 6,000 Russian troops have been killed in Ukraine since the war began on 24 February.

Ukraine says more than 12,000 Russian service personnel have died, while Russia last week acknowledged 498 fatalities – but none of the competing claims can be clearly verified.