Kyiv (Ukraine) (AFP) - Russia's defence minister held rare telephone talks with his US counterpart Friday, after pro-Kremlin officials said they were turning Ukraine's southern city of Kherson into a "fortress" as Kyiv's forces advance.
Few details emerged of the conversation between Russia's Sergei Shoigu and US Defense Secretary Lloyd Austin, but both sides confirmed they had discussed Ukraine.
"Topical issues of international security -- including the situation in Ukraine -- were discussed," said Russia's defence ministry.
"Secretary Austin emphasized the importance of maintaining lines of communication amid the ongoing war against Ukraine," a US military spokesman said.
It was only the second call between the ministers since Moscow invaded Ukraine on February 24. Back in May, Austin had urged Moscow to implement an "immediate ceasefire".
At the time, Russia's invading force had been beaten back from the capital Kyiv but were making steady gains in the eastern Donbas and Kharkiv regions and had consolidated their position in the south.
Six months on, however, Ukraine's forces have pushed back.
Kyiv's forces in recent weeks -- aided by Western weapons -- have been advancing along the west bank of the Dnieper river towards the region's main city Kherson.
The first major city to fall to Moscow's troops, retaking it would be a significant prize in Ukraine's counter-offensive.
Kyiv said Friday it had retaken a total of 88 towns and villages in the region since launching its offensive to retake Kherson in the late summer while President Volodymyr Zelensky welcomed the capture of Russian arms by his forces in the region.
Kherson 'fortress'
Moscow-installed authorities in the region on Friday accused Kyiv's forces of attacking a bridge being used by civilians.
"Four people were killed," pro-Moscow official Kirill Stremousov said on Telegram."The city of Kherson, like a fortress, is preparing for its defence."
Russian investigators said later two of the dead were journalists and that 13 people had been wounded.
A Ukrainian military spokeswoman Nataliya Gumenyuk denied Kyiv's forces were responsible, saying they did not target local populations.
Kyiv has denounced the organised movement of Kherson residents to Russia and other Moscow-controlled regions as "deportations" of Ukrainian citizens.
Zelensky told European leaders Thursday that Russian forces had mined the nearby Kakhovka hydroelectric power plant with the intent of blowing it up.
Its destruction could cause flash-flooding for hundreds of thousands of people, he warned.
On Friday, Ukraine's Prime Minister Denys Shmygal called for an international monitoring mission to deploy at the dam.
Cutting water supplies to the south could also hit the cooling systems of the Zaporizhzhia nuclear power plant, Europe's largest, he added.
Both sides have accused the other of repeatedly shelling the nuclear facility, endangering operations.
Grain shipments 'delayed'
Ukraine's push in the south comes after a sweeping counter-offensive in the northeast Kharkiv region that has badly impaired Russia's supply routes and logistics corridors in the eastern Donbas region.
But Russian forces have continued shelling the region's largest city, Kharkiv, and the presidency said six people were wounded Friday when "industrial infrastructure" was hit in the city.
Also Friday, the Ukraine presidency said Russian forces were shelling sections along the entire front line of Donbas and that two had been killed in the Donetsk region.
And later Friday, Zelensky accused Russia of "deliberately delaying the passage of ships" exporting grain from Ukrainian ports bound for countries in Africa and Asia.
"Russia is doing everything to ensure that at least hundreds of thousands of these people become forced migrants, who will seek asylum...or die of hunger," he said in his nightly video address.
More than 150 ships had been affected, he said, listing Algeria, Bangladesh, China, Egypt, Indonesia, Iraq, Lebanon, Morocco and Tunisia as among the countries hit by the delays.
In late July, Turkey and the United Nations brokered a landmark deal with Moscow and Kyiv that designated three Black Sea ports for Ukraine to send much-needed grain supplies through a Russian blockade.
Russia has complained its own exports have suffered and contended that most deliveries were arriving to Europe, rather than poor countries where grain is most needed.
Moscow's forces have carried out a series of strikes targeting Ukrainian cities and energy infrastructure in recent days with drones the West says were supplied by Iran -- an issue France, Britain and Germany said Friday should be investigated by the United Nations.
The UN ambassadors of the three countries wrote in a letter that they were "deeply concerned by the transfer of unmanned aerial vehicles (UAVs) from Iran to Russia in violation" of a Security Council resolution.
"These UAVs are being used by Russia in its war of aggression against Ukraine in attacks against civilian infrastructure and cities across Ukraine, leading to the death of innocent civilians," they wrote.