Ukraine struck several targets deep inside Russia on Tuesday in what it says is its “most massive” attack of the war so far.

Ammunition depots and chemical plants were hit across several regions, some of which were hundreds of kilometres from the border, according to the General Staff of Ukraine’s Armed Forces.

Sources in Ukraine’s SBU intelligence agency told the BBC the overnight attack was a “painful blow” to Russia’s ability to wage war.

Russia said it had shot down US-supplied Atacms missiles as well as UK-made Storm Shadow cruise missiles, and vowed to respond to the attack.

At least nine airports in central and western Russia temporarily halted traffic, while the strikes prompted schools in the southwestern Saratov region to close.

Strikes in the border region of Bryansk caused explosions at a refinery, ammunition depots and a chemical plant said to produce gunpowder and explosives, a Ukrainian security source told the BBC.

But Kyiv also struck far deeper into the country, with the General Staff claiming to have hit targets up to 1,100km (700 miles) from the border.

In the western region of Saratov, officials reported a “massive” drone attack.