Ukrainian President Volodymyr Zelenskiy said on Thursday that Russia needed to “feel” the consequences of its war as a major Ukrainian incursion across the Russian border stretched into a third day. Pro-Kyiv forces stormed into Russia’s southwestern Kursk region on Tuesday morning, deploying about 1,000 troops and more than two dozen armoured vehicles and tanks, according to the Russian army. It appears to be the most significant Ukrainian attack into Russia since the war began, with independent analysts suggesting Kyiv’s troops had advanced up to 10km into Russia. “Russia brought the war to our land and should feel what it has done,” Zelenskiy said in his evening address, without directly referring to the offensive.

Russian military bloggers, currently the most accurate sources of information, reported that fighting was taking place on the highway east of Korenevo, 13 miles north of the border, while the western part of Sudzha, about six miles into Russia, appeared to be under Ukrainian control. Russia’s defence ministry said on Thursday its forces “continue to eliminate” the Ukrainian attackers in the Sudzha and Korenevo districts, and that it was targeting the invaders with ground forces, artillery, air and missile strikes.

A young man and his 6-year-old brother were killed when a Russian guided bomb hit a schoolyard on Thursday in Ukraine’s northern Sumy region bordering Kursk, after Moscow troops stepped up airstrikes, an official said. Volodymyr Artiukh, head of the Sumy region’s military administration told national TV the area had seen an unprecedented number of airstrikes, referring to 56 guided bombs dropped by Russia in the previous 24 hours.

A man was killed by Ukrainian shelling in the town of Shebekino in Russia’s Belgorod region, Vyacheslav Gladkov, the regional governor, wrote on his Telegram channel on Thursday. He added that another civilian was wounded.

Zelenskiy’s chief of staff said in an interview published on Thursday that a second Kyiv-led peace summit should not be treated as the start of negotiations with Russia. Andriy Yermak, speaking to the media outlet Evropeiska Pravda, said the objective of a second summit would be to agree on a peace plan jointly approved by participants which could then be presented to Russia. “It is possible for a Russian representative to attend the second summit to whom this plan could be handed over,” he said.

Russian shelling killed at least four people on Thursday in Ukraine’s Donetsk region, the focal point of Russia’s slow advance along the eastern part of the frontline. Donetsk regional governor Vadym Filashkin said at least two people were killed in shelling of a residential district of Kostiantynivka, west of Bakhmut, a town which passed into Russian hands a year ago after months of heavy fighting. Filashkin later reported two more killed and 11 injured in Selydove, farther southwest.

Russian internet monitoring services reported mass outages on Thursday of YouTube, a key source of opposition views. Russian lawmakers have blamed Google’s failure to upgrade its equipment in Russia since the 2022 invasion of Ukraine for a slowdown that started in mid-July but the company and technology experts dispute this.

The Mexican president on Thursday rejected a request from Ukraine’s government to arrest Vladimir Putin if the Russian leader defies an international arrest warrant and attends the inauguration of Mexico’s next president in October. “We can’t do that,” President Andrés Manuel López Obrador told reporters at a regular government press conference. “It’s not up to us.”

Russian prosecutors have requested a 15-year prison sentence for a dual US-Russian national charged with “treason” for making a $50 donation to a pro-Ukraine organisation in 2022. The FSB security service said in February it had arrested ballerina Ksenia Karelina, who lives in the United States and was visiting family in Russia, accusing her of providing financial assistance to the Ukrainian army.

Courts in Russia and Russian-controlled territory on Thursday handed long jail terms to Ukrainian accused of attempted “terrorism” and “espionage” in favour of Kyiv. A court in southern Russia found Tetiana Klyuchko guilty of participating in a “terrorist” group and attempting to commit an “act of terror” and sentenced her to 12 years in a penal colony. In the eastern Luhansk region, almost entirely under Russia’s control, the supreme court sentenced Yuriy Galetsky to 13 years in prison for espionage after finding him guilty of handing over information on troop movements.

Ukraine’s foreign ministry on Thursday said it was “a pity” that Niger had decided to break off diplomatic ties, days after neighbouring Mali took a similar decision and accused Ukrainian forces of supporting insurgent groups in the African country. Niger and Mali are both run by military governments that took power in recent coups and have turned to Russia and its Wagner mercenary group for support.