What do we know about drone attacks in Russia?

Russia says Ukraine has launched a series of drone attacks on its territory in recent days.

It accused Ukraine of trying to kill President Vladimir Putin in an alleged drone attack on his residence in the Kremlin on Tuesday.

Two drones were brought down by Russian air defences, according to officials in Moscow, who said Mr Putin was not there at the time.

Ukraine denied carrying out the strike and claimed it was staged by Russia.

In recent months, there have been a number of suspected drone attacks inside Russia and Russian-occupied territory - none have been officially claimed by Ukraine.

An oil refinery in the Krasnodar region of Russia, about 200km (124 miles) from the Crimean border was targeted by drones on 5 May - and the day before - according to Russian media reports.

Last month, a drone came down in the town of Kireyevsk, about 400km (249 miles) from the Ukraine border, injuring at least three people in an explosion after it was brought down, Russian state media said.

A picture of the wreckage appeared to be consistent with a UJ-22 - a type of drone manufactured by Ukraine.

It has a range of 800km (497 miles) in autonomous flight. Its range under directly-controlled flight is much shorter.

In December last year, a drone attack hit an airbase 600km (372 miles) north-east of the Ukrainian border, according to the Russian military.

Since the start of 2023, the BBC - by analysing Russian media reports - has tracked nearly 30 suspected drone attacks inside Russia and Russian-controlled territory in Ukraine.

These have mostly been in the Bryansk and Belgorod regions in Russia near the north-eastern border, as well as in Crimea.

Oil facilities, airfields and energy infrastructure have all been targeted.

We counted five drone strikes on oil depots.

One of these was in Sevastopol, the capital of Russian-controlled Crimea, which was struck on 29 April, destroying several of its oil tanks.

Layla Guest, an analyst at Sibylline security consultancy, says: "Ukrainian forces will highly likely prioritise targeting oil refineries, as well as railway infrastructure and wider Russian logistics, to cause maximum disruption as part of their strategy ahead of the impending counter-offensive."

In terms of range, experts say drones launched from Ukraine could reach deep into Russian territory, and as far as Moscow, which is about 450km (280 miles) from the border.

"Although Ukraine has not confirmed that its armed forces carried out the attacks, I think that the pre-emptive raids we have seen last year prove that Ukraine has the capability to launch long range attacks of that kind from within Ukrainian territory," says David Cenciotti, editor of the Aviationist blog.

Drone specialist Steve Wright also said it was possible that a drone could hit the Kremlin having been launched from within Ukraine.

But he added: "My guess is that the drone was launched from far closer in than that, as this would avoid it having to run the gauntlet of much of Moscow's defences."

Ukraine's Minister for Digital Transformation Mykhailo Fedorov recently boasted of a Ukrainian drone called the R18 that "can fly from Kyiv to Moscow and back".

But he denied that he was calling for drone strikes on Moscow.

Mr Cenciotti says: "Ukraine has made extensive use of several drones, with the Bayraktar TB2 drone emerging as the real star of the air war for Ukraine, inflicting heavy losses on Russian forces, some of those caught on tape and circulated online."

Turkey has sold Bayraktar TB2 armed drones to Ukraine in recent months, while the Turkish manufacturer of the drones has donated some to crowd-funding operations in support of Ukraine.

Additional reporting by Joshua Cheetham, Thomas Spencer, Shayan Sardarizadeh, Paul Brown and Adam Robinson