Russian drones on Thursday hit a major bridge in Kyiv for the first time since the start of the conflict with Ukraine, as Moscow stepped up its attacks on key infrastructure ahead of winter.
The twin strikes happened on the Southern Bridge -- a transport artery connecting the east and west of the Ukrainian capital over the Dnipro river.
Footage shared on Telegram showed an explosion near one of the bridge's support sections and thick smoke rising into the air as road traffic and metro trains crossed.
The bridge was temporarily shut but later reopened, AFP reporters saw.
"According to preliminary inspection results, specialists... did not find any critical damage to the structure," the Kyiv city state administration said.
Russia has intensified drone and missile strikes against Kyiv, putting the capital on a near-constant state of alert against aerial attack.
On Thursday, President Vladimir Putin ruled out a long-range strikes ceasefire with Ukraine.
"We are told: 'Let them stop striking your refineries, and you will stop striking their ships.' It is simply ridiculous," Putin said.
Kyiv on Wednesday said an overnight barrage of Russian strikes on the energy sector was the start of a deliberate campaign designed to cripple the power grid before winter.
Russia has been using jet-powered attack drones that move at high speed and are harder to shoot down than the traditional models, which are based on Iranian Shaheds.
Sergiy Beskrestnov, an adviser to Ukrainian President Volodymyr Zelensky, said Russia was now using drones designed to cut electricity pylons and steel bridge structures.
"I believe that the enemy is planning to attack critical high-voltage power transmission lines," he wrote on Telegram on Wednesday.
Moscow has acknowledged deliberately targeting Ukraine's energy sector -- a tactic it has used repeatedly since its full-scale invasion in February 2022.
Ukraine's nuclear safety watchdog said a Russian drone hit the grounds of the Institute for Nuclear Research in Kyiv on Wednesday but the facility's test reactor was undamaged.
"The fire that resulted from the attack was quickly extinguished. There were no injuries," the regulator said in a statement on Thursday.
"The reactor itself and systems important for safety were not damaged. No changes in radiation levels have been recorded. They remain within the natural background range."
The reactor has been shut down since 2022, it added.
The effect of the strikes on the energy sector and wider civilian infrastructure has prompted many in Ukraine to weigh up their options as winter approaches.
Heating and power were cut for days on end last year as temperatures plunged to -20C. Prime Minister Sergiy Koretsky on Sunday suggested vulnerable and disabled people should consider relocating.
Strikes in recent days have caused power outages in several regions in the east, north and centre, grid operator Ukrenergo said, urging consumers to limit usage even as demand increases with colder weather.
Some emergency power cuts were put in place in Kyiv on Wednesday night.
Ukraine's air force said the number of Russian drone strikes on the country increased in September, with 3,177 attacks up to September 29. In August, 2,850 were recorded.
Residential buildings, petrol stations, the rail network and warehouses have all been hit, with lessons at schools and universities disrupted.
On Thursday, Zelensky, who wants US-made Patriot weapons to intercept the increased aerial threat, said a Russian drone hit a school in Kyiv, causing a fire and damage. Children and teachers were sheltering at the time, he added.
Ukraine is battling to plug a $20-billion hole in its defence budget this year but on Thursday Brussels said it had "identified the means" to unlock EU payments designed to cover the shortfall.
An AFP analysis of data from the Institute for the Study of War meanwhile said Ukrainian troops have regained ground in the Donetsk region, after launching a counteroffensive against Russian forces near Sloviansk and Kramatorsk.
Ukrainian forces seized back 172 square kilometres (66 square miles) since the operation, codenamed "Vivaldi", started last month.