Ukraine cannot protect all of its main cities from Russian missile threats without a significant increase in the provision of air defence systems, according to a key adviser to President Volodymyr Zelenskiy.

Mykhailo Podolyak said the strikes on Odesa over the past week had shown clearly that the Russian strategy was to bombard Ukrainian cities, with the aim of overwhelming air defence systems.

“Russia’s tactics are clear: they use massive drone attacks to overload our anti-aircraft systems and then in parallel they have a window of opportunity to use ballistic missiles to target infrastructure,” he told the Guardian, in an interview at the presidential administration in Kyiv.