The bombardment in the west of Ukraine caused the Polish Armed Forces to scramble its own aircraft, the country’s operational command said on social .
He stopped short of saying who ordered the attack.
More than 130 people were killed in the attack.
The assailants threw explosives, triggering the massive blaze at Crocus City Hall, which can accommodate 6,000, according to Russian news outlets.
There were no immediate claims of responsibility for the raid at the Crocus City Hall, the worst terror attack in Russia in two decades.
RIA Novosti said at least three people in combat fatigues fired weapons.
Many Ukrainians were plunged into darkness across several cities and at least five people were killed.
The deadly attacks on several power facilities have caused widespread outages.
Mr Navalny, the most persistent opponent of President Vladimir Putin, was serving a 19-year sentence when he died.
Ukraine’s Emergency Service said 13 people were wounded, including one child, and that dozens of people were evacuated from their homes.
The governor of Russia’s Belgorod region, Vyacheslev Gladkov, said the children are to be moved further east.
The companies face financial penalties of around 780 thousand Australian dollars (£401,936) per day if they do not comply.
The Kremlin’s forces have made battlefield progress as Kyiv’s troops struggle with a severe shortage of artillery shells and exhausted units.
The new wave of attacks hit the territory on Sunday, killing at least two people including a teenager, according to local officials.
Opposition activists had called for those opposed to the president’s rule and likely extension of his tenure to gather at noon on Sunday.
