Viacheslav Ratynskyi/Reuters
School students attend a lesson as they shelter inside a metro station during an air raid alert, amid Russia's attack on Ukraine, in Kyiv, Ukraine, on May 3.
CNN  — 

Russia unleashed its worst attacks on Kyiv in a year, Ukraine’s military said, as for the third time in four days missiles and drones hit the city.

The barrage came after Moscow accused Ukraine of attempting to assassinate Russian President Vladimir Putin in a drone strike at the Kremlin overnight on Wednesday, allegations Kyiv has vehemently denied.

“Our city has not experienced such a heavy intensity of attacks since the beginning of this year! Last night, the aggressor launched another large-scale air strike on the capital,” Serhiy Popko, head of the Kyiv city military administration, wrote on Telegram.

All Russian missiles and drones “were destroyed in Kyiv airspace by our air defense forces,” Popko said after Moscow attacked the city with “Shahed-type barrage munitions and missiles, presumably ballistic.”

There were no civilian casualties or damage to residential buildings and infrastructure, he added.

Iran has given Russia hundreds of Shahed drones to use in its war in Ukraine. Known as “loitering munition,” the drones are capable of circling for some time in an area before flying their explosive payload toward a chosen target.

Air raid sirens sounded for more than three hours in Kyiv during the attack, Popko said, and explosions were heard in the capital and the southern port city Odesa early Thursday morning, according to Ukrainian parliament member Oleksii Honcharenko.

Ukraine says the drones that struck the city of Odesa had “for Moscow” and “for the Kremlin” written on them, suggesting the overnight strikes across Ukraine may have been relation for the explosions in the Russian capital.

Meanwhile the toll from shelling in the southern Ukrainian city of Kherson rose to 23 people, Oleksandr Prokudin, head of the Kherson regional military administration said.

Russian military shelled the city of Kherson 16 times, including its residential area, according to Prokudin.

Thursday’s pre-dawn raid in Kyiv comes after extraordinary allegations from Moscow that Ukraine launched an attempt to kill Putin with a drone strike on the Kremlin.

Video that appeared on social media shows a bright flash and a puff of smoke over a part of the Kremlin, the official residence of the Russian president and the most potent symbol of power in Moscow.

The Kremlin said the attack was foiled and the alleged drones destroyed. In a statement it regarded the alleged attack as terrorism and a deliberate attempt on Putin’s life. “Russia reserves the right to take retaliatory measures where and when it sees fit,” it added.

The Russian president was not in the building at the time, Kremlin spokesperson Dmitry Peskov said.

Ukraine denied involvement in the alleged strike. “As President Zelensky has stated numerous times before, Ukraine uses all means at its disposal to free its own territory, not to attack others,” the Ukrainian presidential spokesman, Sergiy Nykyforov, told CNN on Wednesday.

Russia on Thursday accused the United States of being behind the attack.

In response to a question from CNN, Kremlin spokesman Dmitry Peskov said: “Such decisions, the definition of goals, the definition of means – all this is dictated to Kyiv from Washington.”

Meanwhile, former Russian official Ilya Ponomarev, who is linked with militant groups in the country, told CNN that he believed the attack was the work of what he calls Russian partisans, not the Ukrainian military.

US officials said they were still assessing the incident, and had no information about who might have been responsible.

Russian oil refinery fires

Also early on Thursday, fires broke out in two oil refineries in southwestern Russia, following separate alleged drone strikes.

At Russia’s Ilsky oil refinery in the southwestern Krasnodar region, a fire ignited in the refinery’s reservoir, according to state-run news agency Tass.

“Due to an attack by an unknown drone, a fuel tank at the Ilsky Oil Refinery in the urban-type settlement of Ilsky in the Seversky district caught fire,” Tass quoted emergency services as saying.

Another drone struck a petrol products plant in Russia near the Ukrainian border during the night, according to Rostov Governor Vasily Golubev. The drone crashed into the construction site of an overpass at the Novoshakhtinsk plant near the village of Kiselevka, causing an explosion and fire, which plant staff immediately extinguished, Golubev said.

It is unclear who is responsible for the drone attack.

It comes after Russian state media on Wednesday said a drone strike ignited a fire that engulfed an oil storage facility in the port of Volna in Krasnodar.

That facility is close to the Kerch bridge that was set ablaze by Ukrainian forces in October 2022. It is unclear how the fuel storage tank caught fire and Ukraine has not commented on the incident.