12 Ukrainians killed in 'biggest ever' Russian drone attack

Russia launched a record number of drones against Ukraine and killed 12 people across the country, officials said on Sunday, even as Kyiv and Moscow completed their biggest prisoner exchange since the start of the war.

Ukraine's emergency services described a night of "terror" as Russia launched a second straight night of massive air strikes, including on the capital Kyiv.

The attacks came even as the two countries completed their biggest prisoner swap since Moscow launched its full-scale invasion in February 2022, with 1,000 captured soldiers and civilian prisoners exchanged by each side.

The death toll from the latest Russian strikes included two children, aged eight and 12, and a 17-year-old, killed in the northwestern region of Zhytomyr, officials said.

Their school named the dead children as Roman, Tamara and Stanislav in a post on Facebook, saying: "Their memory will always be with us. We will never forgive".

"Without truly strong pressure on the Russian leadership, this brutality cannot be stopped," Ukrainian President Volodymyr Zelensky said on social media.

"The silence of America, the silence of others around the world only encourages Putin," he said, adding: "Sanctions will certainly help."

The European Union's top diplomat, Kaja Kallas, called for "the strongest international pressure on Russia to stop this war".

"Last night's attacks again show Russia bent on more suffering and the annihilation of Ukraine. Devastating to see children among innocent victims harmed and killed," she said on social media.