Russia and Ukraine have both reported new battlefield gains, with Ukraine hailing the capture of another village on Russian soil but hundreds of Ukrainians fleeing the eastern city of Pokrovsk as Russian forces advance on it.
Visiting the border area from where his troops entered the Kursk region in western Russia on August 6, President Volodymyr Zelenskiy announced the seizure of a new village that he did not name, and said the incursion had helped reduce Russian shelling of the northeastern Sumy region.
Russian authorities said a Russian ferry sank after a Ukrainian attack that struck southern Russia's Port Kavkaz, which supplies fuel to the occupied peninsula of Crimea.
Seventeen crew members were rescued from the ferry, the Krasnodar region governor said on his Telegram channel.
Ukraine said it had mounted a drone strike on an air base in southern Russia and carried out a raid about 240km from the site of its push into Kursk region.
After returning to Kyiv, Zelenskiy said the latest Ukrainian military action was part of an effort to put an end to the war on Ukraine's terms instead of Russia's.
"This is all our systematic defence path, the path to end this war on the terms of an independent Ukraine," he said in an address to veterans.
He said that to force Russian troops out of Ukrainian territory, the Ukrainian military should "create as many problems as possible" on Russian territory.
But although the incursion is an embarrassment for Russia, its forces have continued their gradual advances of the past few months against tired Ukrainian troops in eastern Ukraine worn down by two and a half years of heavy fighting.
Russia said its troops had taken control of the village of Mezhove in the Donetsk region of eastern Ukraine, and that they had beaten back an attempt by a Ukrainian force to infiltrate its border in a different region to the August 6 incursion.
Ukrainian authorities say Russian troops are now just 10km outside Pokrovsk, an important transport hub in eastern Ukraine, and this week started relocating elderly residents and children.
"Everyone is in panic, people are running away," Liudmyla Sydorenko told Reuters on Thursday as she packed a 94-year-old relative's belongings into plastic bags at their apartment so that she could be relocated.
"I went outside and was shocked: people with paper boxes there, mass evacuation. We don't want to leave, but we have to. We thought we could stay here. It's very difficult."
Russia's capture of Pokrovsk, which lies at an intersection of roads and a railway line, would give it options to advance in new directions and also cut supply routes used by the Ukrainian military in the Donetsk region.
Authorities in Kursk said they had begun installing concrete shelters to help protect civilians during the Ukrainian incursion.
President Vladimir Putin accused Ukraine of trying to strike Russia's Kursk nuclear power plant in an overnight attack and said the United Nations nuclear safety watchdog had been informed about the situation.
The International Atomic Energy Agency (IAEA) said on Thursday its director general Rafael Grossi would assess the situation there during his visit next week.
The IAEA also said it had been informed by Russia that the remains of a drone had been found within the Kursk nuclear power plant.
Acting Kursk governor Alexei Smirnov told Putin the situation at the Kursk plant was "stable".
Reuters was unable to independently confirm the attack or reports from the battlefield.
Ukraine has closely guarded its main aims in the Kursk region but said it has carved out a buffer zone from an area that Russia has used to pound targets in Ukraine with cross-border strikes.
Military analysts say the incursion probably aims in part to divert Russian forces to ease pressure in the east, although there is no indication Russia has pulled troops from there.
The incursion has boosted morale among Ukrainians as they prepare to mark 33 years since independence from the Soviet Union on Saturday.
Meanwhiel, Ukraine said representatives of more than 40 countries and international organisations took part in a meeting on Thursday to follow up on a peace summit hosted by Switzerland in June.
Thursday's meeting, which took place online, was the first in a series of working group sessions stemming from the Switzerland summit.
