Kyiv says 'thousands' of troops involved in Kursk surprise attack

Ukrainian sources indicated that thousands of troops had been committed to its incursion into Russia, which on its sixth day appeared to edge forward - with reports of fighting 15 to 18 miles inside the border and a rare video showing the capture of a village close to the border on a new aspect of the front.

- Dan Sabbagh

A Ukrainian security official told the Agence France-Presse news agency that the aim of the incursion was to destabilise Russia and string out its forces with light, fast-moving attacks. However, it remains unclear how sustainable the operation is in the medium term amid Kremlin threats that it will be snuffed out with Russian reserves.

Russia had suggested that several hundred Ukrainian troops had launched a surprise attack on Tuesday, but the Ukrainian official said that the numbers involved were larger. Asked if more than 1,000 Ukrainian soldiers were involved, the official said: "It is a lot more...thousands."

Several Ukrainian brigades are said to be involved in the operation, in which Kyiv caught Russia off-guard by striking at a lightly defended sector of the front where there had been no significant fighting since the spring of 2022 - and broke through limited border defences.

"We are on the offensive. The aim is to stretch the positions of the enemy, to inflict maximum losses and to destabilise the situation in Russia as they are unable to protect their own border," the security official said on condition of anonymity.