Heraldo de Madrid - Reuters team member killed in strike on east Ukraine hotel

Ukraine meanwhile accused neighbouring Moscow-allied Belarus -- which allowed Russia to use its territory as a launchpad for the February 2022 invasion -- of "concentrating" troops on the border and warned it to stop "unfriendly" actions.

In another bloody day in the two-and-a-half year war, Russian attacks killed at least 18 civilians across Ukraine, while Russian officials said six civilians were also killed in Ukrainian strikes on Russian border regions.

Reuters said it was "devastated" by the loss of its security advisor following the strike late on Saturday at the Hotel Sapphire in the city of Kramatorsk, where six of its crew covering the war were staying.

Ukrainian President Volodymyr Zelensky denounced the strike.

"For all this, the world must not stop putting pressure on the terrorist state," he said, referring to Russia following its 2022 invasion of Ukraine.

Reuters said the strike left two of its journalists in hospital, one with serious injuries, while three others were safe.

Ukrainian prosecutors said the hotel was hit by a Russian Iskander missile at 10:35 pm (1935 GMT) on Saturday, with the strike also damaging the building next door.

Kramatorsk -- the last major city under Ukrainian control in the Donetsk region -- is often used as a base for aid workers and foreign journalists.

Reuters said the advisor who was killed had "helped keep so many of our journalists safe as they covered events around the world. He was a dear colleague and friend, and we will miss him terribly."

- Ukraine claims Kursk advances -

Kyiv meanwhile claimed further advances into Russia's Kursk region, where it launched a counter-offensive on August 6.

Zelensky claimed Ukraine's surprise incursion into Kursk had yielded small advances -- "from one to three kilometres" -- and taken control of two more Russian settlements.

Catching Russia off-guard, Kyiv's incursion has rattled Moscow and displaced more than 130,000 people, but has not slowed the Russian troops' advance in eastern Ukraine.

- 'Scary to go to bed' -

In Kramatorsk, AFP saw authorities handing out plywood to locals for them to board up their windows.

The city lies around 20 kilometres (13 miles) from the front line, with fears over the city rising as Russian forces continue their push into eastern Ukraine.

Many locals were heading to bed at the time of the strike.

"I was watching a film on my phone and then... there was such a noise and the glass started smashing," 66-year-old Natalia told AFP, crying.

She said she had already been evacuated once after a similar experience but came back, and now will "think about" leaving again.

"It's scary to go to bed," she said, her voice breaking.

Another resident, 84-year-old Vasily who lives close to the hotel, was fixing plywood onto his window frames after the glass smashed during the strike.

"We worry all the time... and now our turn has come," he said, adding: "It's about how lucky you get."

- Belarus warned against 'unfriendly actions' -

Late on Sunday, Kyiv said Ukrainian intelligence had found Belarus was building up equipment and troops on the border "under the guise of exercises".

The foreign ministry said Ukrainian intelligence had also recorded the presence of fighters from the Wagner mercenary group -- some of whom are being hosted by Belarus after their leader's failed rebellion last year.

It warned Minsk to "cease unfriendly actions and withdraw forces away from Ukraine's state border".

In 2022, Minsk allowed Russian troops to station in Belarus for "drills" before Moscow launched its invasion in February.

Ukraine also said that military exercises in the border area pose a "global security" threat due to the Chernobyl Nuclear Power plant nearby -- site of the world's worst nuclear disaster.

On Sunday evening, officials said attacks on the Sumy region -- from where Kyiv had launched its surprise incursion on August 6 -- had killed three civilians and wounded six more.

In the south, officials said Russian strikes that hit outside the city of Kherson killed three people and wounded six, including a one-year-old boy who was left with shrapnel injuries.

Belgorod governor Vyacheslav Gladkov said five people were killed in a strike on the village of Rakitnoye, in an attack that also wounded 13 others.

Gladkov later said a man was killed by a Ukrainian drone attack in the village of Solovyevka further south.

M.Soler--HdM