Civilians were evacuated on Sunday from a vast steel factory in the war-battered Ukrainian port city of Mariupol, President Volodymyr Zelensky and aid officials said.
An initial group of about 100 civilians were taken out of the sprawling premises of the Azovstal factory and moved to a "controlled area," Zelensky tweeted.
"Tomorrow we'll meet them in Zaporizhzhia. Grateful to our team!" he said. Zaporizhzhia is about 200 kilometres to the north-west of Mariupol.
The International Committee of the Red Cross (ICRC) confirmed it was working with the United Nations to transport trapped civilians through a safe corridor.
Meanwhile, a new attempt to transport civilians to Zaporizhzhia from Mariupol that was scheduled for Sunday afternoon was postponed, local officials said.
Zaporizhzhia is under Russian control. It has been the destination for previous evacuation operations.
"I hope that tomorrow all the necessary conditions will be met to continue the evacuation of people from Mariupol," Zelensky said in a video message later on Sunday, adding that the plan was to start evacuations at 8 am local time.
"We will continue to do everything to evacuate our people from Azovstal, from Mariupol in general," the president added.
The Russian Defence Ministry, meanwhile, said about 80 people had been taken to the village of Bezimenne, between Mariupol and the Russian border, where they were cared for. The action took place at the initiative of Kremlin leader Vladimir Putin, the ministry said. Those who wanted to go to the area controlled by Ukrainian troops were handed over to representatives of the UN and the ICRC, it said.
Russia and Ukraine had reported on Saturday that a few dozen civilians had managed to leave. But Sunday's efforts were more substantial and more coordinated, kindling hopes that a wider operation could follow.
Mariupol, a strategic port city, has been under relentless Russian bombardment for weeks. The Azovstal factory, with its large network of underground tunnels and bunkers, is the only remaining stronghold of Ukrainian resistance in Mariupol. Many of the fighters are injured.
Civilians, including families with children, had also taken shelter at the site. Messages emerging from the embattled plant in recent days told of food and water shortages - and fears that those inside would not survive the Russian siege.
According to Ukrainian officials, about 1,000 civilians were trapped in the plant's underground network. Russia speaks of about 2,500 people and says many of them are military personnel and "foreign mercenaries."
Russia and Ukraine have repeatedly blamed each other for the failure to get civilians out of the factory. UN Secretary General António Guterres had pressed for a solution during visits to Moscow and Kiev last week.
Russia has already largely captured Mariupol. According to estimates, about 100,000 of its once 440,000 inhabitants still remain there. Their situation is considered catastrophic.
While much of the focus was on Mariupol on Sunday, the grinding war continued across parts of Ukraine.
The Russian government reported that anti-aircraft missile systems were destroyed in the Zaporizhzhia area and that two fighter jets were shot down in the Kharkiv region.
The Ukrainian military said it repelled a series of Russian attacks around the major southern city, UNIAN news agency reported Sunday evening.
Russian units made several unsuccessful attempts to surround Ukrainian troops east of Zaporizhzhia and numerous residential buildings and electricity and phone networks were damaged during fighting, regional administrator Oleksandr Starukh was quoted as saying.
The Defence Ministry in Moscow also reported an attack on an airfield in the Black Sea metropolis of Odessa, with missiles destroying the runway and a hangar where weapons from the West had been stored. Ukraine confirmed that shelling had taken place.
The Ukrainian army said it fired missiles at the Russian-occupied Snake Island in the Black Sea, killing 42 Russian soldiers. Several air defence complexes and a communications unit were destroyed.
The claims by the Russian and Ukrainian militaries are difficult to verify.
Russia, meanwhile, accuses Ukraine of increasingly launching attacks on Russian territory.
On Sunday, a fire at a military facility near the western Russian city of Belgorod was reported.
The fire broke out "on the territory of an object of the Ministry of Defence of the Russian Federation," Governor Vyacheslav Gladkov wrote on Telegram, adding later that seven buildings were damaged.
Military targets in Russia close to the Ukrainian border have been repeatedly fired upon in recent weeks. An oil depot in Belgorod burnt down at the beginning of April, which Russia blamed on Ukraine, which did not confirm the attack.
Russia also claimed Ukraine attacked the Russian region of Kursk on Saturday.