Russia said Wednesday it had shot down two drones aimed at Vladimir Putin's residence in the Kremlin in what it called a "terrorist" assassination attempt against the Russian president.
"Two unmanned vehicles were aimed at the Kremlin... the devices were put out of action," the Kremlin said in a statement, adding that this had happened during the night between Tuesday and Wednesday.
The remnants of the downed drones fell inside the Kremlin but did not injure anyone, the statement added.
It said the operation was "a planned terrorist act and an attempt on the life of the President of the Russian Federation."
Kremlin spokesman Dmitry Peskov said Putin was working at his residence near Moscow on Wednesday and would still take part in a scheduled WWII Victory Day parade on Red Square next week as planned.
Moscow's mayor announced a ban on unauthorised drone flights over the Russian capital.
In a statement, mayor Sergei Sobyanin said drone flights would be prohibited unless a special permit had been obtained from "government authorities".
The Kremlin news came as Ukraine prepared for a fresh offensive against Russian troops that has been months in planning.
In possible signs that preparations are being stepped up, the frontline city of Kherson in southern Ukraine announced a long curfew for residents and sabotage acts behind Russian lines intensified.
Kherson, which was re-taken by Ukrainian troops in November, will be under curfew from Friday evening until Monday morning.
Regional officials said this was "for law enforcement officers to do their job", but similar long curfews have also been used in the past for troop and arms movements.
"During these 58 hours, it is forbidden to move on the streets of the city. The city will also be closed for entry and exit," the head of Kherson's regional military administration, Oleksandr Prokudin, said on Telegram.
He advised residents to stock up on food and medicine and said people could go for short walks near their houses or visit shops but should carry identity documents with them at all times.
The curfew announcement came as officials said three people were killed and five injured in a Russian strike on Kherson's only working hypermarket on Wednesday.
Kherson was captured by Russian troops last year in the first days of the invasion and remained under Russian occupation until November 2022.
After a sustained campaign of sabotage attacks behind Russian lines, Russian forces withdrew from the city.
They crossed to the eastern side of the Dnipro River which now delineates part of the front line in southern Ukraine.
The curfew announcement came as officials in Russia said they were dealing with a major fire at a fuel depot close to the bridge to Russian-annexed Crimea -- the second such incident in just a few days.
A source in the emergency services was quoted by TASS news agency as saying that the fire had been caused by a drone.
An explosion also caused a freight train to derail in a southern Russian region bordering Ukraine on Tuesday, also the second such incident in just two days.
Ukraine says it has been preparing for months for a counteroffensive aimed at repelling Russian forces from the territory they currently hold in the east and south.
Meanwhile in Finland, NATO's newest member, Ukrainian President Volodymyr Zelensky was on a surprise visit to take part in a summit with the leaders of the five Nordic nations which have been key providers of military aid.
"In order to be in NATO and support alliances to gain support, fundamental diplomatic work must be done. Ukraine is doing it today," Daria Zarivna, Ukraine's presidential communications adviser, wrote on Telegram.
