Russia has arrested eight people on suspicion of involvement in an explosion which destroyed part of a key bridge linking the country to annexed Crimea.
Moscow’s Federal Security Service (FSB) said on Wednesday that it had detained five Russians and three citizens of Ukraine and Armenia over the blast on the Kerch road-and-rail bridge.
The FSB claimed the attack was organised by Ukrainian military intelligence and its director, Kyrylo Budanov. The explosive device was moved from Ukraine to Russia via Bulgaria, Georgia and Armenia, the FSB said.
One section of the road bridge on the 19 kilometre stretch was obliterated and several fuel tankers heading to Crimea from Russia went up in flames.
The incident occurred shortly after 6am local time (4am UK time) on Saturday, killing three people. It was branded a “terrorist act” by Russian President Vladimir Putin, who accused Kyiv of being the mastermind and launched a barrage of missiles in retaliation.
The deadly strikes prompted Ukrainian President Volodymyr Zelenskyy to appeal to G7 leaders to establish an “air shield” over his country.
Opened by Mr Putin in 2018, the bridge serves as a vital link between Russian and the Black Sea territory it annexed in 2014. Since Russia invaded Ukraine in February, the Kremlin has relied on the Kerch bridge to transport military equipment to forces fighting in southern Ukraine.
The FSB, which is the main successor to the Soviet-era KGB, also said that it had prevented Ukrainian attacks in Moscow and the western Russian city of Bryansk.
Ukraine has not officially confirmed its involvement in the bridge blast, but some officials have celebrated the damage.
Senior Ukrainian official Oleksiy Danilov, joked that the explosion was a birthday present to Mr Putin, who turned 70 last Friday. The national security and defence council secretary posted a video of flames rising from the bridge alongside a clip of Marilyn Monroe singing “happy birthday Mr President” from a 1962 event in honour of John F Kennedy.
Mykhailo Podolyak, an adviser to President Zelenskyy, tweeted a photo of the damaged bridge and said: "Everything illegal must be destroyed, everything stolen must be returned to Ukraine, everything occupied by Russia must be expelled."
In retaliation for the blast, Russia pounded 10 cities in Ukraine with 83 missiles on Monday, killing at least 19 people and injuring more than 100. Kyiv was among the locations targeted for the first time in months, while the eastern city of Lviv, around 64 kilometres from the Polish border, also came under attack.
Maciej Wasik, Poland’s interior minister, said his government was inspecting bomb shelters to make sure they were fit for purpose, but insisted the checks were “routine”. Warsaw is preparing for the “darkest scenarios” regardless of how likely they are to occur, he said.
Power supply sites were also targeted in the widespread strikes.
At a televised meeting of Russia's Security Council on Monday, Mr Putin said the operation was retaliation for the Crimea bridge blast, which he said had been organised by Ukraine's secret services.
A spokesman for the main intelligence directorate of the Ukrainian Ministry of Defence, Andriy Yusov, rubbished the Russian accusations.
"All the activities of the FSB and [Russia's] Investigative Committee are nonsense," he was quoted in Ukrainian media saying. "They are fake structures which serve the Putin regime, so we're definitely not going to comment on their latest announcements."
Mr Zelenskyy on Tuesday appealed to wealthy western countries to help Kyiv create an “air shield”, telling G7 leaders that “millions of people would be grateful” for help fending off attacks from the sky. He said without such protection the Russian military “still has room for further escalation” after Monday's missile salvoes.
Washington has pledged to increase shipments of air defences to Kyiv, while Germany promised delivery “in the coming days” of the first Iris-T missile shield reportedly capable of protecting a city.
In a week of marked escalation in the war, G7 leaders said that Belarus's plan to deploy joint forces with Russia constituted a new instance of “complicity” with Moscow, warning Minsk to “stop enabling” Russia's invasion.
Following talks with Mr Zelenskyy, G7 leaders said they would hold Mr Putin to account for attacks, but declined to specify how.
Before the G7 meeting, the Kremlin had already said it expected “confrontation” with the West to continue.
Russia followed up the missile launches at the start of the week with further aerial attacks on Tuesday.
Seven people were killed on Wednesday after Russian missiles hit a market in Avdiivka, a city in the eastern Ukrainian region of Donetsk.
Russians struck the central market, where many people were at that time," Pavlo Kyrylenko, regional governor of Donetsk, said. He said there was "no military logic" to the attack. He said it showed Moscow's "unbridled desire to kill as many people as possible" in Ukraine.