UKRAINIAN artillery fire targeted the pro-Russian Donetsk “people’s republic” government headquarters as the bitter fight for control of the Donbass continued today.

Four districts of Donetsk came under attack in the early afternoon, local authorities said, with transport networks shut down. 

On Saturday, some 20 civilians were killed. Shelling of residential areas intensified as Ukrainian President Volodomyr Zelensky vowed to retake control of eastern and southern Ukraine.

An area the size of England has fallen to Russia since its invasion began in February.

Two firefighters were among those killed as they battled to control fires resulting from the attacks, while two children were said to be among those injured in an attack on Komsomolskoye.

Local reports said the rockets were fired from French-supplied Caesar self-propelled artillery mounts and M-777 howitzers sent to Ukraine from other Nato countries. 

Nato secretary-general Jens Stoltenberg has reiterated calls for more weapons to be sent to Ukraine as he told Western countries to prepare for a long war.  

He conceded that the costs of war were high, but said the price of letting Russia achieve its military goals was even greater. 

“We must prepare for the fact that it could take years. We must not let up in supporting Ukraine," Mr Stoltenberg said in an interview with German newspaper Bild. 

“Even if the costs are high, not only for military support, also because of rising energy and food prices.”

The Nato chief said that increasing weapons supplies to Ukraine could help it liberate the eastern Donbass region, much of which is under Russian control. 

Ukrainian forces appeared closer to defeat in Severodonetsk which is on the front line of the battle for the east. 

Ambassador of the self-declared Lugansk People’s Republic (LPR) to Russia Rodion Miroshnik said that neonazis from the Aidar battalion and their leaders had surrendered in the city’s suburbs yesterday.

It is believed that they have been transferred to Russia for questioning. Russian news agency Tass said Azov Battalion fighters from Mariupol had also been sent to Russia.

Mr Miroshnik also said that “very serious blows are being inflicted to the outskirts of Lisichansk.” 

Ukrainian forces holed up at the Azot plant chemical plant are signalling that they are ready to continue negotiations, he added. 

Mr Zelensky made his first trip to Ukraine's war-torn southern front line, visiting Mikolaiv on Saturday where he met soldiers, local officials and health workers. 

Ukrainian forces are failing to make advances there although the Kiev government has dismissed reports of hundreds of soldiers being killed every day. 

It said the Ukrainian officials that made those remarks do not have access to the appropriate information.