Ukrainian President Volodymyr Zelensky ruled out the possibility of talks with Russia on Friday after a visiting delegation of African leaders urged both countries to de-escalate.

The diplomatic team came to Kyiv to voice the concerns of a continent that has suffered from the fallout of Russia's attack – in particular from rising grain prices – with South African President Cyril Ramaphosa insisting "there should be peace through negotiations".

But Zelensky rejected that possibility during a joint press conference, telling reporters: "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".

Shortly after the African leaders' arrival, air raid sirens sounded across the country as Russian missiles were detected, forcing the delegates to take shelter in the capital.

Zelensky said the strike on Kyiv during the delegation's visit was evidence that Putin either did not control his army, or was "irrational".

Ramaphosa, however, took the barrage as evidence that both sides needed to stop fighting.

"It is precisely that type of event that we saw today... that makes us call for de-escalation," Ramaphosa said, quoting Nelson Mandela several times on the need for peace.

In a statement, Zelensky said he had called on the leaders to set out their views on how to stop the "crimes committed by Russia", and how to work towards food security.

"But first of all, we must restore the full force of the UN Charter and stop this brutal Russian aggression and free our land," he added.

The African delegation includes four presidents: Ramaphosa, Senegal's Macky Sall, Zambia's Hakainde Hichilema and Comoros' Azali Assoumani, who also currently heads the African Union.

The leaders of Uganda, Egypt and Congo-Brazzaville pulled out of the visit at the last moment and sent representatives instead. (AFP)