KYIV, Ukraine — 

On the eve of Ukraine’s independence day and the half-year mark of Russia’s invasion of its neighbor, unease grew in the country Tuesday that Moscow could target specific government and civilian targets during the holiday.

The U.S. reinforced those concerns when its embassy in Kyiv issued a security alert, saying it “has information that Russia is stepping up efforts to launch strikes against Ukraine’s civilian infrastructure and government facilities in the coming days.”

On Tuesday’s national Flag Day, President Volodymyr Zelensky stressed defiance rather than worry when he raised the flag at a memorial.

“The blue-and-yellow flag of Ukraine will again fly where it rightfully should be — in all temporarily occupied cities and villages of Ukraine,” he said, including the Crimea peninsula, which Russia annexed in 2014.

Over the weekend, Zelensky warned of a coming threat when he said in his daily address that “we should be aware that this week Russia may try to do something particularly nasty, something particularly cruel.”

The U.S. Embassy’s warning came on the heels of Russia’s claim that Ukrainian intelligence was responsible for the car bombing that killed the daughter of a leading right-wing Russian political thinker over the weekend. Ukraine denied involvement.