It comes as North Korean troops are in Russia fighting against Ukraine, according to Ukrainian and other military sources.
Mr Zelensky said in a post on Telegram that he asked the pope for support for children and adults imprisoned by Russia.
Two schools in the town, about 70 kilometres from the Polish border, were also damaged.
Russian jets, ammunition depots and fuel supplies have been hit.
Polish Foreign Minister Radosław Sikorski said thousands of Ukrainian citizens in Poland had joined a planned volunteer brigade.
The body of a missing boy has been retrieved from the rubble of an apartment block in Kyiv that was destroyed in a Russian missile attack.
An anonymous report said the coup planned to occupy Ukraine’s parliament during a demonstration and set up a “provisional government.”
The north-eastern Ukrainian city which has been the target of Russian airstrikes for months was hit by two glide bombs.
The Council of the EU approved the suspension of the import duties on Ukrainian exports.
SBU head Vasyl Malyuk said the attack was supposed to be “a gift to Putin before the inauguration.” Vladimir Putin was sworn in as Russia’s president on Tuesday.
