At least 15 people have been killed in Russian attacks on Ukraine, including 10 killed in ballistic missile attacks on an exhibition near kyiv showcasing drone technology.

Ukrainian President Volodymyr Zelensky said About 100 people were injured in the Daytime attack on the exhibition, attended by prominent members of the defense sector.

Five people were also killed by Russian glide bombs in the eastern city of Slaviansk. Early Saturday, military officials confirmed the deaths of two men in the northern city of Sumy.

On Friday night, Zelensky said he had received information that Russia was preparing another massive missile attack, which could occur “in the next 48 hours.”

Ukrainian attack overnight Thursday killed six people and wounded 26 people in the Russian city of Kirov, more than 1,000 kilometers (600 miles) behind the front line. Ukraine also attacked the warehouses of Wildberries, Russia’s largest online retailer.

After the attacks near kyiv, there were initially fears for the safety of Defense Ministry adviser Serhiy Beskrestnov, also known as Flash, and Lyuba Shypovych, who has been involved in developing technology for the Ukrainian military.

After the incident, the pair took to social media to confirm they were unharmed, with Beskrestnov saying he had stayed away from the event for safety reasons.

Ukrainian air force spokesman Yuri Ihnat told Ukrainian television that the attack involved three ballistic missiles, of which only one was intercepted.

Russia confirmed the attack. Its Defense Ministry said high-precision, long-range weaponry had been used at a site where drones were being demonstrated to attack civilian sites in Russia.

He said drone producers were present, as well as representatives of Ukraine’s drone forces and security services that “plan and carry out attacks directly on Russian territory.”

This is at least the third time since the large-scale Russian invasion in 2022 that such an exhibition has been affected.

There has been widespread outrage that such a public event was taking place and was apparently widely publicised.

President Zelensky said the incident was being investigated, while Ukraine’s prosecutor general said efforts were being made to establish who decided to hold the event and what security measures were in place.