President Volodymyr Zelenskiy on Saturday said that Russian forces were preparing an impending massive attack on Ukraine and warned residents to take special care as Russian strikes in different regions killed at least six people. “Tonight and in the coming hours, it is especially important to pay close attention to air raid warnings,” Zelenskiy said in his nightly video address. “The Russians have prepared for a massive attack. Please take care of yourselves.” Russian forces have staged a series of heavy attacks on Kyiv in the past few weeks and in other major cities. Strikes on Monday last week killed 10 people throughout the country and badly damaged the Pechersk Lavra monastery, a 1,000-year-old monastery that stands as a symbol of Ukrainian spiritual and cultural heritage.

An emergency psychologist talks to a resident at the site of an apartment building hit by a Russian airstrike amid Russia’s invasion of Ukraine in Kharkiv on Saturday.

Zelenskiy has pledged that his military would press on with its campaign of medium and long-range strikes, focused on the oil sector. Ukrainian drones on Saturday struck an oil refinery in Tyumen region in western Siberia and also struck Moscow’s oil refinery twice last week, Zelenskiy said.