Russia has intensified strikes on Ukraine overnight, with widespread attacks across the country affecting most regions.

At least 12 people, including three children, were killed and dozens injured in Russian drone and missile strikes, regional officials and emergency services said.

The attack was the second large-scale assault on the country in 48 hours, coming a day after the Ukrainian capital Kyiv suffered one of the heaviest assaults since the start of the Russian invasion.

Saturday's strikes, which killed 13 people across Ukraine, come as diplomatic efforts to end the fighting have resulted in prisoner exchanges, but Russia has not accepted calls for a ceasefire.

Russian President Vladimir Putin launched a full-scale invasion of Ukraine in February 2022, and Moscow currently controls about 20% of Ukrainian territory.

This includes Crimea - Ukraine's southern peninsula annexed by Russia in 2014.

Ukraine's air force said that since 20:40 on Saturday local time (17:40 GMT), Russia had carried out strikes using 367 missiles of various types, unmanned aerial vehicles (UAVs) and drones.

The air force said it had shot down 45 cruise missiles and neutralised 266 UAVs, with most regions in Ukraine affected.

The air force recorded hits in 22 locations and downed cruise missiles and UAVs in 15 areas.

The strikes mark an intensification from the previous night, when Ukraine's air force said Russia attacked with 14 ballistic missiles and 250 UAV and drones, affecting six regions.

Deaths were reported in multiple regions after Saturday's overnight strikes.

In the Kyiv region, four people were killed and 16 injured, including three children, Ukraine's state emergencies service DSNS said.

Kyiv regional head Mykola Kalashnyk posted photos on social media of several houses set ablaze after the Russian strikes.

In the capital, Kyiv, local officials reported 11 injuries, multiple fires and damage to residential buildings, including a dormitory.

Hundreds of people were seen sheltering in underground stations of the city's metro. It comes as the capital marks its annual Kyiv Day holiday on Sunday.

Khmelnytskyi regional head Serhiy Tyurin said on Facebook that four people were killed and five were injured.

"Six private houses were destroyed, and another 20 damaged," he added.

In Zhytomyr, DSNS said three children aged eight, 12 and 17 were killed, 10 people injured and private homes "destroyed and damaged".

DSNS also said the body of an elderly man was pulled out from a five-storey residential building hit by a drone in Mykolaiv. Another five people were injured.

In Kharkiv, regional authorities reported three injuries.

In Russia, the defence ministry said 110 Ukrainian drones were destroyed and intercepted over 12 Russian regions and the Crimea peninsula between midnight and 0700 local time.

Moscow Mayor Sergei Sobyanin reported that 12 drones heading towards the capital were shot down.

He added that emergency services crews were deployed to assess damage caused by falling drone debris.

In the Tula region, just south of Moscow, drone wreckage crashed in the courtyard of a residential building, smashing windows in a number of apartments, local governor Dmitriy Milyaev said.

No-one was injured, he added.

The attacks came as Russia and Ukraine take part in prisoner swaps agreed after talks between the two sides in Turkey.

On Friday, Ukraine and Russia each handed over 390 soldiers and civilians in the biggest prisoner exchange since Russia launched its full-scale assault in February 2022.

On Saturday, Ukrainian President Volodymyr Zelensky announced that another 307 Ukrainian prisoners had returned home as part of an exchange deal with the Kremlin.

The two countries have agreed to swap a total of 1,000 prisoners each, and another exchange is expected on Sunday.

The swap follows the first face-to-face talks between the two sides in three years, which took place in Turkey.

Earlier this week, US President Donald Trump and Putin had a two-hour phone call to discuss a US-proposed Ukraine ceasefire deal.

Trump said he believed the call had gone "very well", and added that Russia and Ukraine will "immediately start" negotiations toward a ceasefire and "an end to the war".

However, Putin has only said Russia would work with Ukraine to craft a "memorandum" on a "possible future peace", and has not accepted a 30-day ceasefire.