Russia-Ukraine conflict: Kyiv under fire as NATO leaders visit capital

Russia's offensive in Ukraine edged closer to central Kyiv on Tuesday, with a series of strikes hitting a residential neighbourhood as the leaders of three NATO member countries planned a visit to the embattled capital.

Shortly before dawn, large explosions thundered across Kyiv from what Ukrainian authorities said was artillery strikes.

At least one person was killed and many others remained trapped inside as shelling ignited a huge fire and a frantic rescue effort in a 15-story apartment building.

Shockwaves from an explosion also damaged the entry to a downtown subway station that has been used as a bomb shelter.

City authorities tweeted an image of the blown-out facade, saying trains would no longer stop at the station.

The leaders of Poland, the Czech Republic and Slovakia will on Tuesday travel to the Ukrainian capital on a European Union mission to show support for the country as Russia's forces move closer to Kyiv.

The aim of the visit is to express the EU's unequivocal support for Ukraine and its freedom and independence, Czech Prime Minister Petr Fiala tweeted.

He will be joined by Slovak Prime Minister Janez Jana, Polish Prime Minister Mateusz Morawiecki and Jaroslaw Kaczynski, Poland's deputy prime minister for security and the leader of the conservative ruling party.

Russian and Ukrainian negotiators also planned to hold a second day of talks as the offensive in Ukraine entered its 21st day.

When Russia launched the war nearly three weeks ago, fear of an imminent invasion gripped the Ukrainian capital, as residents slept night after night in subway stations or crammed onto trains to flee. But as the Russian offensive bogged down, Kyiv saw a relative lull. Fighting has intensified on the outskirts in recent days, and sporadic air raid sirens ring out around the capital.

There was a rare glimmer of hope in the encircled port city of Mariupol after a convoy of 160 civilian cars left along a designated humanitarian route, the city council reported.

Over the past 10 days or so, the lethal siege has pulverised homes and other buildings and left people desperate for food, water, heat and medicine.

The negotiations held on Monday by video between Russia and Ukraine were the fourth round involving higher-level officials from the two countries and the first in a week.

The talks ended without a breakthrough after several hours, with an aide to Ukrainian President Volodymyr Zelenskyy saying the negotiators took a technical pause and planned to meet again on Tuesday.

The two sides had expressed some optimism in the past few days. Mykhailo Podolyak, the aide to Zelenskyy, tweeted that the negotiators would discuss peace, cease-fire, immediate withdrawal of troops, and security guarantees.

Zelenskyy is seeking to extend martial law until April 24 and to require men aged between 18 and 60 to stay in the country to fight. Zelenskyy submitted the extension in a bill to parliament, which is expected to vote on it this week.

In Kyiv, the early morning explosions hit the Svyatoshynskyi district of western Kyiv, adjacent to the suburb of Irpin that has seen some of the worst battles of the war.

Russian forces also stepped up strikes overnight on the northwest suburbs of Irpin, Hostomel and Bucha, said the head of the Kyiv region, Oleksiy Kuleba.

Many streets (in those areas) have been turned into a mush of steel and concrete. People have been hiding for weeks in basements, and are afraid to go out even for evacuations, Kuleba said.

Ukrainian authorities said two people were killed when the Russians struck an airplane factory in Kyiv, sparking a large fire. The Antonov factory is Ukraine's largest aircraft plant and produces many of the world's biggest cargo planes.

Airstrikes were reported across the country, including the southern city of Mykolaiv, and the northern city of Chernihiv, where heat was knocked out to most of the town. Explosions also reverberated overnight around the Russian-occupied Black Sea port of Kherson.

In Mariupol, where the war has produced some of the greatest suffering, the city council did not say how many people were in the convoy of cars headed westward for Zaporizhzhia. But it said a cease-fire along the route appeared to be holding.

Previous attempts to evacuate civilians and deliver humanitarian aid to the southern city of 430,000 were thwarted by fighting.

Ukraine's military said it repelled an attempt on Monday to take control of Mariupol by Russian forces, who were forced to retreat.

Ukraine claimed its forces had killed 150 Russian troops and destroyed two Russian tanks in the battle for Mariupol.

The Kremlin-backed leader of the Russian region of Chechnya said on a messaging app that Chechen fighters were spearheading the offensive on Mariupol.

Robert Mardini, director-general of the International Committee of the Red Cross, said the war had become nothing short of a nightmare" for those living in besieged cities, and he pleaded for safe corridors for civilians to leave and humanitarian aid to be brought in.

The situation cannot, cannot continue like this, he said. History is watching what is happening in Mariupol and other cities.

The Russian military said 20 civilians in the separatist-controlled city of Donetsk in eastern Ukraine were killed by a ballistic missile launched by Ukrainian forces. The claim could not be independently verified.

The UN has recorded at least 596 civilian deaths since the February 24 invasion of Ukraine by Russian forces. The agency however believes the true toll is much higher.

Millions more have fled their homes, with more than 2.8 million people crossing into Poland and other neighbouring countries in what the UN has called Europe's biggest refugee crisis since World War II.