Russia launched a large-scale aerial assault on Ukraine’s capital Kyiv in the early hours of Thursday, marking a second consecutive night of ferocious attacks on the country, as Russia ramps up its bombardment more than three years into the war.

Russia has recently sought to overwhelm Ukraine’s air defenses with major attacks that include increasing numbers of decoy drones. The pressure has caused alarm among Ukrainian officials who are uncertain about continuing vital military aid from the United States.

US Secretary of State Marco Rubio is scheduled to meet his Russian counterpart Thursday as the US prepares to send more weapons to Ukraine to help it fend off attacks from the Kremlin’s war machine.