Ukraine remains in control of the Azot chemical plant in Sievierodonetsk where hundreds of civilians are sheltering, the region’s governor says.

A Russia-backed separatist previously said 300 to 400 Ukrainian fighters were trapped there.

“The information about the blockade of the Azot plant is a lie,” Serhiy Gaidai, governor of the Luhansk region partially controlled by pro-Russian separatists, said on the Telegram messaging app on Saturday.

“Our forces are holding an industrial zone of Sievierodonetsk and are destroying the Russian army in the town,” he wrote.

Sievierodonetsk, a small city in the region, has become the focus of Russia’s advance in eastern Ukraine and one of the bloodiest flashpoints in a war now into its fourth month.

Ukraine has said some 800 people were hiding in several bomb shelters underneath the Azot plant, including about 200 employees and 600 residents of Sievierodonetsk.

Rodion Miroshnik, a Russian-backed representative of the self-proclaimed Luhansk People’s Republic, said late on Saturday that some civilians had started to leave.

“There are occasional exchanges of fire … they (the Ukrainian defenders) may still be holding several hundred civilians hostage,” he said in an online post. Reuters was not immediately able to verify his account.

Miroshnik had earlier said 300 to 400 Ukrainian fighters were blockaded on the grounds of the plant along with civilians and had tried to negotiate their passage to Lysychansk, Sievierodonetsk’s twin city. 

Ukraine has appealed for swifter deliveries of heavy weapons from overseas to turn the tide of the war with Russian forces – which it says have at least 10 times more artillery pieces than Ukrainian forces.

Yet even when outgunned, Ukraine’s army has proved more resilient than expected in early phases of fighting.

“We are definitely going to prevail in this war that Russia has started,” Ukrainian President Volodymyr Zelenskiy told a conference in Singapore via videolink.

“It is on the battlefields in Ukraine that the future rules of this world are being decided.”

Meanwhile, the self-proclaimed Donetsk People’s Republic (DPR) said a verdict on a captured South Korean “mercenary” was being prepared, Russia’s Interfax news agency reported.

The family of one of the two UK fighters sentenced to death in a brief court appearance last week said on Saturday they were “devastated and saddened at the outcome of the illegal show trial” and called for Shaun Pinner to be treated as a prisoner of war and released or exchanged.

The conflict between the neighbours – two of the world’s biggest grain exporters – has reverberated well beyond Ukraine.

“If due to Russian blockades, we are unable to export our foodstuffs, which is so sorely missing in global markets, the world will face an acute and severe food crisis and famine – famine in many countries of Asia and Africa,” Zelenskiy told the Shangri-La Dialogue conference in Singapore.

The United Nations said on Friday up to 19 million more people in the world could face chronic hunger in the next year because of reduced wheat and other food exports.

Ukraine’s deputy agriculture minister said on Saturday up to 300,000 tonnes of grain may have been stored in warehouses in the Black Sea port of Mykolaiv tha were reportedly destroyed by Russian shelling last weekend.