The two countries have forged an informal alliance against the United States and other democratic nations that is now complicated by the Israel-Hamas war.
A Russian rocket struck a village cafe and store in eastern Ukraine on Thursday and killed at least 50 civilians in one of the deadliest attacks in months, according to President Zelenskyy and other top officials in Kyiv.
The militarisation of Russia's public schools has intensified since the Russian invasion of Ukraine, driven not by a spontaneous surge of patriotic feeling, but by the government in Moscow.
Ukrainian President Volodymyr Zelenskyy vowed on Sunday a stern retaliation to the Russian missile strike in the centre of the northern Ukrainian city of Chernihiv that killed seven people and wounded over a hundred others the day before.
Ukrainian sea drones attacked a major naval base in Russia on Friday, leaving a damaged Russian warship listing in the Black Sea in a brazen strike carried out hundreds of kilometres from Ukrainian-held territory.
Russian forces pounded a key village that Ukraine claimed to have recaptured in its grinding counteroffensive in the country's southeast, while Moscow accused Kyiv of firing two missiles at southern Russia.
The ambassador, Vadym Prystaiko, had criticised Zelenskyy over his reaction to recent remarks by British Defence Secretary Ben Wallace, who had suggested Ukraine had not expressed sufficient "gratitude" for Western financial support.
Australian Prime Minister Anthony Albanese said Russia's "illegal" and "immoral" invasion of Ukraine is a big theme of the NATO Summit as he reaffirmed Australia's support for the people of Ukraine.
A Russian submarine commander shot to death while jogging on Monday may have been targeted by an assailant tracking him on a popular running app, according to Russian media.