Explosions rock Kyiv and Ukraine second city Kharkiv

Flames lit up the night sky on the outskirts of Ukraine's capital, Kyiv, on Saturday after an oil terminal was hit by a missile attack.

The massive explosion in Vasylkiv, 18 miles (30km) south of Kyiv, prompted warnings of toxic chemical fumes, reports BBC.

Those nearby were warned to close their windows - though many in Kyiv are already sheltering underground.

A strict curfew was enforced in the city on Saturday and is in place until Monday.

BBC producer Kathy Long said Sunday dawned cold and quiet there, with police, the military and armed volunteers the only people visible on the streets.

But the blue and yellow national flag still flies on many of the ornate buildings that make up Kyiv's skyline, as the country enters its fourth day under Russian invasion.

In underground car parks, metro stations and basements, thousands are waiting to assess the damage the darkness brought. It will have been a cold, cramped and uncomfortable night for many underneath their homes, listening for the sounds of gunfire and thudding missiles, the uncertainty and fear growing.

Away from the capital, missiles battered several cities overnight - including Ukraine's second-largest, Kharkiv, close to the Russian border.

Russian troops blew up a natural gas pipeline there, according to a Ukrainian state communications agency.

A nine-storey residential tower was also hit in Kharkiv overnight, emergency services said. The building was severely damaged and an elderly woman was killed, but rescuers said about 60 people were spared injury as they had taken refuge in the basement.

In another northeastern city, Okhtyrka, the local governor said at least six Ukrainians - including a seven-year-old girl - had died as a result of a Russian attack on Friday.

A kindergarten and an orphanage were among the reported targets, which Russia has denied.

Ukraine's Foreign Minister Dmytro Kuleba has alleged war crimes and called for an investigation by the International Criminal Court.

The fighting across Ukraine has resulted in at least 240 civilian casualties, including 64 deaths, according to the Office of the United Nations High Commissioner for Human Rights (OCHCR).

It added that damage to homes and critical infrastructure has left hundreds of people without access to water and electricity.

Tens of thousands of Ukrainians have been pouring towards neighbouring countries to escape the war. More than 115,000 have crossed into Poland alone - some travelling for more than two days, and others joining queues 15km (10 miles) long at border points.

Those fleeing are mostly women and children, as all Ukrainian men aged 18 to 60 are being told to stay and fight.

Despite the Russian onslaught, Ukraine's defences have held for another night.

According to a US-based war monitor, Russia has "failed to encircle and isolate Kyiv with mechanised and airborne attacks as it had clearly planned to do".

The Study of War's latest assessment said Russian attacks on other cities in the northeast and east have failed because they were "poorly designed and executed", and they faced "more determined and effective resistance than expected" from Ukrainian forces.

The monitor added that Russia's successes in the south of Ukraine posed the most danger.