Russian forces have launched a major offensive in the Donetsk region of eastern Ukraine, the Ukrainian general staff reported in its situation report on Friday morning.
"The enemy is conducting an offensive operation in the direction of Bakhmut and Avdiivka in the Donetsk area," the report said. The push was aimed at positioning Russian forces for an assault on Soledar and Bakhmut and expanding Russian control to the west of the city of Donetsk, it added.
Soledar and Bakhmut form part of the defensive line to the east of the conurbations of the major cities of Slovyansk and Kramatorsk, which were home to more than half a million people before the war.
The region is the last still under the control of Ukrainian government forces in the wider eastern Donbass region and has been heavily fortified by the Ukrainian side.
The general staff report said the Russian assault near Bakhmut had been without success, while fighting was continuing on the approaches to Avdiivka, directly to the north of Donetsk city.
The report could not be independently confirmed but was in line with earlier reports of increased fighting in the region following a brief pause.
In southern Ukraine, authorities announced a more than two-day curfew on the port city of Mykolaiv to root out those aiding the Russian army there.
"Over the weekend, the city will be closed, buy water and food in time. We are working, also with regard to collaborators," Governor Vitalii Kim said in a video message on Friday. According to the statement, the general curfew will be in effect from 11 pm on Friday until 5 am on Monday (2000-0200 GMT). The governor had already announced the curfew in July.
Mykolaiv is being shelled almost daily by the Russian army from a distance of about 25 kilometres. According to Ukrainian authorities, almost exclusively civilian objects are hit. The city had almost 500,000 inhabitants before the war.
Moscow and Kiev meanwhile traded accusations of blame for the shelling of the Russian-occupied nuclear power plant in Zaporizhzhya, south-eastern Ukraine.
Several Russian news agencies reported on Friday afternoon that the Ukrainian army had shelled the site, citing the administration of the city of Enerhodar, where the power plant is located.
Two power lines had been broken and a fire had broken out, according to the reports. The information could not be independently verified.
The Ukrainian side in contrast said that the Russians had shelled the site themselves. As a result, a high-voltage line to the neighbouring thermal power plant was damaged, Ukrainian state nuclear company Enerhoatom said. One block of the nuclear power plant had been shut down.
The mayor of Enerhodar, Dmytro Orlov, who fled, warned remaining citizens that residential areas were being shelled from the power plant site.
Russian forces were likely jeopardizing the security and safety at the Zaporizhzhya plant, the British Ministry of Defence said in an intelligence update published Friday.
"Following five months of occupation, Russia's intentions regarding the Zaporizhzhya Nuclear Power Plant remain unclear," it said. "However, the actions they have undertaken at the facility have likely undermined the security and safety of the plant's normal operations."
Russian forces had used artillery units based in areas near the power station to target Ukrainian territory on the west bank of the Dnipro river, the report said.
It added that the Russians had used the area around the plant, in particular the adjacent city of Enerhodar, to rest their forces, "utilizing the protected status of the nuclear power plant to reduce the risk to their equipment and personnel from overnight Ukrainian attacks."
Meanwhile in Russia, President Vladimir Putin received his Turkish counterpart Recep Tayyip Erdoğan for talks in the Black Sea resort of Sochi.
Ahead of the meeting, Putin thanked Türkiye's president for his role in mediating a recent deal to resume grain exports from Ukraine's Black Sea ports, which had been blocked for months following Russia's invasion of its neighbour Ukraine.