Russia battling major Ukraine border incursion for third day

Russia's army was fighting a major Ukrainian border incursion for the third day running, Moscow said Thursday, with independent analysts saying Kiev's troops had advanced up to 10 kilometres (six miles) into Russia.

Pro-Kiev forces stormed into Russia's southwestern Kursk region on Tuesday morning, deploying around 1,000 troops and more than two dozen armoured vehicles and tanks, according to the Russian army.

It appears to be the most significant of several cross-border attacks mounted by Ukraine since Russia launched its full-scale military offensive in February 2022.

Russia's defense ministry said Thursday its troops were "continuing to destroy" armed Ukrainian units and were using air strikes, rocket and artillery fire to try to push them back.

It said it had rushed in reserves and was "thwarting attempts to break through" deeper into the Kursk region.

The independent U.S.-based Institute for the Study of War (ISW) said Ukraine had made significant territorial gains in the first two days of the incursion.

"Ukrainian forces have made confirmed advances up to 10 kilometres (six miles) into Russia's Kursk Oblast amid continued mechanised offensive operations on Russian territory," it said in its latest update.

"The current confirmed extent and location of Ukrainian advances in Kursk Oblast indicate that Ukrainian forces have penetrated at least two Russian defensive lines and a stronghold," it added.

Kiev has not officially taken responsibility for the operation, but an aide to Ukrainian President Volodymyr Zelensky said Moscow was to blame for the incursion.

"The root cause of any escalation, shelling, military actions, forced evacuations and destruction of normal life forms -- including within the...