Ukraine's cross-border raid on Russia explained

Hello. As fighting continues in Russia's Kursk border region, James Waterhouse examines the logic behind Ukraine's attack. Meanwhile, from Moscow, Steve Rosenberg assesses what the surprise incursion says about Russia's war. In Qatar, Rushdi Abualouf witnessed Hamas’s shadowy veterans vote for their new leader - he recounts what unfolded. And scroll down for birds, crabs, monkeys and a (stolen) howling wolf.

QUESTIONS ANSWERED

What's behind Ukraine's surprise foray

The incursion is more likely to be about diverting Russian resources, than occupying land. Credit: Getty Images

Heavy fighting in Russia's Kursk region has entered a third day, with the defence ministry saying efforts are "ongoing" to expel at least 1,000 Ukrainian forces, along with tanks and armoured vehicles. Some 3,000 people have had to evacuate the region, with at least four killed, local officials have said.

What's been the reaction to the incursion?

The question from some military experts was: "Why?" One of Ukraine's biggest battlefield issues is manpower. Russia has more soldiers and is inching closer to the eastern Ukrainian town of Pokrovsk. So, sending hundreds of Ukrainian soldiers into Russia itself is, shall we say, counterintuitive in the eyes of some.

What are others saying?

Mykhaylo Zhyrokhov, a military analyst, told the BBC that Russia had been forced to redeploy some troops there from the front line in eastern Ukraine. "If you look at official reports, there were significantly fewer Russian glide bombs dropped in the Donetsk area," he said. "That means the aircraft which carry them are now elsewhere in Russia."

What other factors are there?

Russia launched a major cross-border offensive of its own into Ukraine's north-eastern Kharkiv region. The advance seems to have slowed after the US gave Ukraine permission to use its missiles on targets inside Russia. Ukrainian fears of a similar attack into the northern Sumy region have been mounting in the subsequent three months.

Analysis: That the incursion seems to have taken Russia's political and military leadership by surprise is another sign the war is not going to plan for Moscow, writes Steve Rosenberg.

THE BIG PICTURE

Studying the secrets of hovering kestrels

Motion-capture technology has enabled researchers to observe two Nankeen Kestrels in a wind tunnel. Credit: RMIT University

For bird-lovers like me, the site of a kestrel hovering over a verge as it eyes up its prey is always a treat. But researchers studying the birds' ability to "hang" in the air reckon it could help aviation engineers work out how to equip delivery drones to deal with unpredictable city winds.

And finally... in London

Street artist Banksy has unveiled two new graffiti works in London as part of a series that, as the BBC understands, is set to conclude at the end of this week. Like his previous two stencil artworks, they feature animals - a trio of monkeys in east London and a howling wolf, in south-east London. However, it seems the latter - painted onto a satellite dish - has fallen victim to what might be the least sophisticated art heist in history. Place your bets on where the final pieces will appear - my colleague Sofia hopes there will be one near her home in the north-west of the city.