Russia accused Ukraine on Wednesday of a failed attempt to assassinate President Vladimir Putin in a drone attack on the Kremlin citadel in Moscow, and threatened retaliation.
Kyiv denied any role in the reported incident, with a senior aide to President Volodymyr Zelensky calling it a sign the Kremlin was planning a major new attack on Ukraine. "We don't attack Putin, or Moscow, we fight on our territory," Zelensky told a news conference in Helsinki.
Shortly after the Kremlin announcement, Ukraine reported alerts for air strikes over Kyiv and other cities.
"Two unmanned aerial vehicles were aimed at the Kremlin. As a result of timely actions taken by the military and special services with the use of radar warfare systems, the devices were put out of action," the Kremlin said in a statement.
Claims of drone attacks
"We regard these actions as a planned terrorist act and an attempt on the president's life, carried out on the eve of Victory Day, the May 9 Parade, at which the presence of foreign guests is also planned," it said.
It said fragments of drones were scattered in the Kremlin grounds but there were no injuries or damage.
Putin himself was safe.
"The Russian side reserves the right to take retaliatory measures where and when it sees fit."
Video posted by Baza, a Telegram channel with links to Russia's law enforcement agencies, showed a flying object approaching the dome of a Kremlin building overlooking Red Square, exploding in a burst of light just before reaching it.
Other video posted on a neighborhood internet group showed a plume of smoke over the Kremlin's gold domes. Reuters could not independently verify the videos.
In comments sent to Reuters, Ukrainian presidential advisor Mykhailo Podolyak said: "Of course, Ukraine has nothing to do with drone attacks on the Kremlin. We do not attack the Kremlin because, first of all, it does not resolve any military tasks."
Podolyak said the accusation, along with a separate announcement that Russia had caught suspected saboteurs in Crimea, "clearly indicates the preparation of a large-scale terrorist provocation by Russia in the coming days."
Drone war
Elsewhere, oil depots were ablaze in both southern Russia and Ukraine, as both sides escalated a drone war ahead of Kyiv's promised spring counteroffensive.
Scores of firefighters battled a huge fire that Russian authorities blamed on a Ukrainian drone crashing into an oil terminal on Russia's side of its bridge to occupied Crimea. A fuel depot in Ukraine was ablaze after a suspected Russian drone strike on the central city of Kropyvnytskyi.
An administrative building in Ukraine's southern Dnipropetrovsk region was also hit by a drone and set on fire. Ukraine said it had shot down 21 of 26 Iranian-made drones in an overnight volley, shielding targets in the capital Kyiv where air raid sirens blared for hours through the night.
Zelensky was greeted by cheering crowds in Finland's capital Helsinki, where he arrived on a rare trip abroad to meet Nordic leaders, some of Ukraine's strongest supporters.
Ukraine and Russia have both been launching long-range strikes since last week in apparent anticipation of Ukraine's upcoming counteroffensive, which Zelensky said would begin soon.
After a lull of nearly two months, Russia began a new wave of long-range attacks with missiles last Friday, including one that killed 23 civilians while they slept in an apartment building in the city of Uman hundreds of miles from the front.
Since then, a suspected Ukrainian drone strike caused a fire at a Russian oil terminal in occupied Crimea, Russia hit dozens of homes and an industrial enterprise in Ukraine's Dnipropetrovsk region, and blasts derailed freight trains in Russia's Bryansk region adjacent to Ukraine two days in a row.
Moscow says its long-range attacks have struck military targets, though it has produced no evidence to support this. Kyiv, without confirming any role in incidents in Russia or occupied Crimea, says destroying infrastructure is part of the preparation for its planned ground assault.
Fire of 'highest rank'
In videos posted on Russian social media of the burning fuel depot near the Crimea bridge, flames and black smoke billowed over large tanks emblazoned with red warnings of "Flammable."
"The fire has been classified as the highest rank of difficulty," said Veniamin Kondratyev, governor of the Krasnodar region, adding that there were no casualties, people should remain calm and there was no need to evacuate.
In Ukraine, the governor of the central Kirovohrad region said three Russian drones had tried to hit an oil facility in the region's main city Kropyvnytskyi. Prosecutors said a huge blaze had broken out there.
Zelensky's visit to Finland was his fourth known trip abroad since Russia's full-scale invasion. Leaders of Denmark, Iceland, Norway and Sweden also attended. Zelensky said his goals were to beef up Ukraine's military and secure an eventual place in the NATO alliance.
The Nordic countries have been among the strongest supporters of Ukraine since the invasion, with Finland and Sweden both applying to join NATO in response to a war Moscow claimed was aimed in part at blocking the alliance's expansion.
Zelensky, who has also visited the United States, Britain, France, Poland, and the EU's headquarters in Belgium, is due in Germany on May 13.
Russia says it launched its "special military operation" to counter a threat from Kyiv's relations with the West. Ukraine and its allies call it an unprovoked war of conquest by Moscow, derailed by a failed assault on the capital Kyiv early last year and Ukrainian advances in the second half of 2022.
Over the past five months, Ukrainian ground forces have kept mostly to the defensive, while Russia launched a huge, largely unsuccessful winter assault, capturing little new ground despite the bloodiest infantry combat in Europe since World War Two.
For its planned counterattack, Kyiv has been building up a force with thousands of fresh troops trained at Western bases and armed with hundreds of new Western-supplied tanks and armored vehicles.
US Secretary of State Antony Blinken on Wednesday said he can not validate Russia's accusation that Ukraine tried to assassinate Russian President Vladimir Putin in a drone attack, but said he would take anything coming from the Kremlin with a "very large shaker of salt."
Asked if the United States would criticize Ukraine if it decided on its own to strike back in Russian territory, Blinken said those were decisions for Ukraine to make about how to defend itself.
White House: can't confirm whether Ukraine attacked Kremlin with drones
The White House said on Wednesday it was aware of reports that Russia accused Ukraine of attacking the Kremlin with drones to try to kill President Vladimir Putin but could not authenticate or confirm the allegations.
"We are aware of the reports but are unable to confirm the ... authenticity of them at this time," White House spokesperson Karine Jean-Pierre told reporters.