At least seven people have been killed including two children during intense Russian drone and missile strikes on Ukraine, officials say.

A kindergarten was hit in Ukraine's second biggest city Kharkiv and there was widespread damage in Kyiv. Children were among the 27 people wounded.

Hours earlier, US President Donald Trump said his plans for an imminent summit in Budapest with Russia's Vladimir Putin had been shelved as he did not want a "wasted meeting".

President Volodymyr Zelensky said the attacks proved Moscow had not come under enough pressure for its continued war.

The Kremlin has rejected calls for a ceasefire along the current front lines made both by Trump and European leaders.

However, Russian officials said on Wednesday that preparation for a Trump-Putin summit was continuing, disputing the US president's assessment that it had been put on hold.

Kremlin spokesman Dmitry Peskov said a date had yet to be agreed upon and careful preparation was needed.

He said a summit was "the mutual desire of both presidents" and most of the "gossip and rumours" surrounding it were untrue.

Ukraine's president arrived in Norway on Wednesday at the start of a European trip, days after talks with Trump in Washington last Friday, when he failed to persuade the US president to provide long-range Tomahawk missiles.

Zelensky told reporters in Oslo that Trump's proposal to freeze the front line was a "good compromise, but I'm not sure that Putin will support it and I said it to the president".

The Ukrainian leader has directly linked the shelving of the planned Trump-Putin summit to his request for US Tomahawks: "As soon as the issue of long-range missiles became a little further away for us, for Ukraine, then almost automatically Russia became less interested in diplomacy."

Russia's drone and missile bombardment came shortly after Ukraine's military said it had attacked a Russian chemical plant in the Bryansk border region late on Tuesday with UK-supplied Storm Shadow missiles.

Calling the strike "a successful hit" that penetrated the Russian air defence system, military officials said the Bryansk plant "produces gunpowder, explosives and rocket fuel components used in ammunition and missiles employed by the enemy to shell the territory of Ukraine".

Russia launched a full-scale invasion of Ukraine in February 2022, and its attacks on the Ukrainian capital overnight were the first such strikes for almost two weeks.

A couple in their 60s were killed when a drone hit their high-rise building in the city, and four people were killed in the wider Kyiv region.

Among the victims were a 36-year-old woman, a six-month-old baby and a girl, aged 12, when a Russian strike set fire to their house in the village of Pohreby, just to the north of the capital. A man in a nearby village later died of his injuries.

Officials in Kharkiv said later that a 40-year-old man was killed and seven other people were hurt in a drone strike on a kindergarten. Children were among the six people wounded, and dozens more were evacuated, they added.

Ukraine's air force said Russia had sent 405 drones and 28 missiles, 15 of which were ballistic.

The capital was under a ballistic missile warning for most of the night, and echoed to the sound of explosions. By morning rescue teams fought fires in residential buildings.

Across Ukraine, Russian attacks once again targeted energy infrastructure and emergency power outages were imposed in several areas.

One MP in Kyiv, Inna Sovsun, told the BBC's Newsday programme that the air raids had lasted throughout the night and were definitely an attack on the power supply: "for the majority like myself it means we don't have electricity and we don't have water."