Ukrainian President Volodymyr Zelensky has ruled out talks with Russia as he met with a delegation of African leaders.
"I clearly said several times at our meeting that to allow any negotiations with Russia now that the occupier is on our land is to freeze the war, to freeze pain and suffering," Mr Zelensky told reporters after meeting several leaders including South Africa's Cyril Ramaphosa.
Mr Ramaphosa called on Ukraine and Russia to end the conflict, as he arrived in the war-torn country.
"This war must be settled and there should be peace through negotiations," he told reporters after the talks.
The delegation is to also meet Russian President Vladimir Putin.
They arrived in Kyiv on a mission to broker peace, first visiting the nearby town of Bucha, where Russian troops have been accused of massacring civilians.
Air raid sirens sounded across Ukraine after they arrived on this morning and the air force said it had downed 12 Russian missiles.
There were no reported damage inside the city, but three people were wounded in the surrounding region, the Interior Ministry said.
Mr Zelensky said that Russia's missile strike on Kyiv as the African delegation visited meant that Mr Putin did not control Russia's army or that he was "irrational", adding he wanted to "fully destroy the state of Ukraine".
The head of Mr Zelensky's presidential office, Andriy Yermak, wrote that Mr Putin "is ready to disregard the security of foreign leaders, he doesn't really care, because he feels complete impunity".
"We remember that missiles were also flying when US President Joe Biden and UN Secretary-General Antonio Guterres arrived in Ukraine," he added.
Mr Zelensky accused Russia of managing to freeze the Ukraine conflict after annexing the peninsula of Crimea in 2014, adding that Kyiv would not allow Moscow to do this again.
Russia taking heavy losses in south, says Ukraine
Advancing Ukrainian troops are facing "desperate resistance" from Russian forces around the eastern city of Bakhmut and are inflicting big losses on Russian troops in the south, Ukrainian military chiefs said.
Colonel General Oleksandr Syrskyi, who is in charge of Ukrainian ground forces, said the situation in the east was tense and Russia was bringing its best divisions into the Bakhmut sector with backup from artillery and aircraft.
"We continue to conduct offensive actions in separate directions, occupying dominant heights, and strips of forest with the aim of forcing the enemy gradually out of the outskirts of Bakhmut.
Realising this, the enemy units put up desperate resistance," Mr Syrskyi said on the Telegram messaging app.
The small, ruined city of Bakhmut has seen some of the fiercest and bloodiest fighting since Russia's full-scale invasion in February 2022.
The Ukrainian military said last week it had started to push Russian forces back around Bakhmut.
Mr Syrskyi said Ukrainian forces were also advancing in the south.
Kyiv said yesterday that it had regained control of about 100 square km of territory in just over a week of its counter-offensive against Russian forces.
Brigadier General Oleksandr Tarnavskyi, commander of Ukrainian troops in the southern Tavriia sector, said there had been 36 combat engagements and 578 attacks in the past 24 hours in the sector.
Putin dismisses Ukraine gains
Russia has not officially acknowledged Ukrainian advances in the early stages of a counter-offensive and said it had inflicted heavy losses on Kyiv's forces in the previous 24 hours.
Mr Putin said Ukraine's counter-offensive would fail as Kyiv's troops sought to advance in several directions, including the southeastern region of Zaporizhzhia.
"I think that Ukraine's armed forces stand no chance here, as well as in other directions -- I have no doubt about that," Putin told an annual economic forum in Saint Petersburg.
"In some places Ukrainian units are managing to reach the first line (of defence), in other places they are failing," Mr Putin said.
"They are using the so-called strategic reserves," he added.
Putin said Ukrainian forces did not achieve their objectives in any section of the front, adding: "That's the important thing."
