Moscow’s ambassador to London has said the UK is waging a proxy war against Russia, while predicting the “end of Ukraine” as Russian invading forces make deeper advances into the country.

In an interview with the BBC, Andrei Kelin said Ukraine continued to fight but claimed “the resistance is more feeble and feeble”.

Russian troops, he said, were gaining more terrain every day, adding: “The end of this phase will mean the end of Ukraine.” Russia is thought to control about 18% of Ukraine and has been making slow but steady advances over the last year.

Kelin also described the conflict as “a proxy war led by the United Kingdom’s government” which by providing weapons is “killing Russian soldiers and civilians”.

The comments came as Ukraine’s president, Volodymyr Zelenskyy, renewed his appeal to western countries for air-defence systems, after Russian missile strikes on the central city of Kryvyi Rih late on Saturday wounded 17 people, according to Ukrainian officials.

Ukraine is losing its territory in its eastern Donbas region to Russia’s invading forces, while coming under sustained bombardment, but has yet to convince western allies to provide it with long-range missiles to strike Russian military targets.

In Kryvyi Rih, Zelenskyy’s home town, a police officer and rescue worker were among those injured in Russian attacks that damaged sites including an administrative building, a hotel and an educational facility, Ukraine’s national police reported on social media.

The regional governor, Serhiy Lysak, said later that 15 apartment buildings, stores, a cafe, a church, office spaces, a bank branch and a gas pipeline had been damaged in the city.

In a social media post on Sunday, Zelenskyy said that in the last week Russia had used more than 20 missiles of different types, about 800 guided aerial bombs, more than 500 varying strike drones against Ukraine. “Ukraine needs more air defence systems and long-range capabilities. I am grateful to all partners who understand this and support us,” he wrote on X.

His post was accompanied with a 47-second video showing numerous smashed-up cars, burning buildings and bombed out homes in seven Ukrainian regions, described as the result of a week of Russian attacks.

Meanwhile, the Russian defence ministry said that 110 drones were destroyed in an overnight barrage against seven Russian regions. Many targeted Russia’s border region of Kursk, where 43 drones were reportedly shot down, but others appeared to go much further

Gleb Nikitin, the governor of Nizhny Novgorod, a city 250 miles (250km) east of Moscow, wrote on Telegram that four fighters had been lightly injured repelling a drone attack over an industrial zone, and were later discharged. He did not go into further details.

The Associated Press new agency reported that social media footage appeared to show air defences at work over the city of Dzerzhinsk in the Nizhny Novgorod region, close to a factory producing explosives.

In Kyiv, officials reported that about 10 drones were destroyed near the capital, with no known destruction or injuries.

Visiting Kyiv on Saturday, France’s foreign minister, Jean-Noël Barrot, pledged support for Ukraine’s plan for ending the war with Russia, telling reporters he would work to secure other nations’ backing for the proposals.

Outlining his “victory plan” this week, Zelenskyy called for an “immediate” invitation to join Nato to guarantee Ukraine’s security, but western allies have given a guarded response. Moscow claimed the plan amounted to an escalation, by “pushing Nato into direct conflict” with Russia.

Russia’s ambassador to the UK was speaking to the BBC after the opening of a public inquiry into the death of Dawn Sturgess. She died in 2018 after coming into contact with the nerve agent novichok, believed to have been in a perfume bottle discarded by Russian agents who had tried to assassinate the former Russian spy Sergei Skripal and his daughter Yulia in Salisbury a few months earlier.

The inquest into Sturgess’s death was converted into a public inquiry in 2021 and opened last Monday.

The UK government told the inquiry this week in a statement that it considered the Russian president, Vladimir Putin, had authorised the Salisbury novichok poisonings, which could have killed thousands of people.

The Russian government has denied any involved in the attempted assassination of the Skripals and poisoning of Sturgess and her partner, Charlie Rowley, who survived.

Asked in the BBC interview if he had any words for Sturgess’s grieving family, the ambassador said: “I don’t know. I have never met this family. I am not involved in discussions with them or anything else. If someone has died of course we are concerned about that.”

He also questioned the need for an inquiry: “Why drag this history so long?”

The Skripal poisonings are seen as a turning point in British perceptions of Russia, triggering what the then prime minister, Theresa May, described as “the largest collective expulsion of Russian intelligence officers in history”.

More than 100 Russian diplomats working in 20 western countries, who were alleged to be spies, were told to return to Moscow in a show of solidarity by western allies.