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 preparations for a Trump-Putin summit were 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.

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.

Following a meeting on Wednesday, Zelensky and Swedish Prime Minister Ulf Kristersson signed a letter of intent that could see Sweden supply 100 to 150 Gripen fighter jets to 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, following a Russian strike that set fire to their house.

Officials in Kharkiv stated that a 40-year-old man was killed and seven others injured in a drone strike on a kindergarten. Ukraine's air force reported that Russia sent 405 drones and 28 missiles, 15 of which were ballistic, in a night of significant bombardment.

This violence comes as diplomatic discussions continue regarding the ongoing conflict in Ukraine, illustrating the complex interplay of military action and geopolitical negotiations.