KYIV, Ukraine—Explosions rocked Ukraine’s capital on Thursday after Russia launched a fresh barrage of missiles at targets across the country, as officials in Moscow warned of consequences for Western pledges to send dozens of battle tanks to Ukraine.

Air-raid sirens rang out across Ukraine during the morning rush hour, with officials urging residents to seek shelter underground. In Kyiv, Mayor Vitali Klitschko said at least one person died and two were injured when a rocket hit the city’s Golosiivsky district, parts of which were engulfed in black smoke following the blast.