Russia has intensified nightly airstrikes over the past week ahead of a renewed Ukrainian counter-offensive.
Air raid sirens have been heard in the capital Kyiv and two-thirds of Ukraine as Russia’s renewed air campaign continues for more than a week.
Ukrainian emergency services issued air raid alerts early Tuesday for Kyiv and most of central and eastern Ukraine, stretching from Vynnitsya in the west to all eastern regions and south to Kherson and the Odessa region on the Black Sea, reported the Reuters news agency.
Kiev officials said the city’s air defenses were working to repel the attack.
At least four people were killed on Monday when Russia sent a wave of drones and missiles into Ukraine in the early hours of the morning.
It stepped up its air campaign on April 28 amid reports that Kiev would soon launch a new counter-offensive to recapture Russian-held territories.
At least 8,791 civilians have been killed since Russia invaded Ukraine in February last year, according to the United Nations. Thousands more were injured and millions were driven from their homes.
Russia has been embroiled for months in a desperate battle for control of the devastated eastern city of Bakhmut, which it sees as key to its further advance in the east.
Wagner’s mercenary group led the attack, and Yevgeny Prigozhin, the group’s leader, recently released a series of profanity-laden videos blaming Defense Minister Sergei Shoigu and Chief of General Staff Valery Gerasimov for withholding ammunition.
On Tuesday, he released another video saying the guns still hadn’t arrived.
“The people who were supposed to fulfill the (shipping) orders have not fulfilled them in the last day,” Prigozhin said in the Telegram post.
Russian President Vladimir Putin will preside over Victory Day celebrations in Moscow later on Tuesday, when he is expected to address thousands of troops standing at attention in Moscow’s Red Square.
The traditional military parade marks the victory of the Soviet Union over Nazi Germany in 1945.
At least six post-Soviet leaders, including the Prime Minister of Armenia and the President of Kazakhstan, are expected to attend the event this year.