Russia launched a massive overnight missile and drone attack on Kyiv and surrounding areas, killing at least 16 people and wounding dozens, Ukrainian officials said Thursday.

The hourslong assault involved ballistic and cruise missiles as well as fast-moving, jet-powered drones, placing intense pressure on Ukraine’s air defense systems.

Kyiv was the primary target of the attack, with explosions heard across the capital throughout the night. Ukraine’s air force said strikes were recorded at 28 locations across the country.

Emergency officials reported that 15 people were killed in Kyiv, while another person died in the surrounding Kyiv region. President Volodymyr Zelenskyy said about 40 people were wounded.

Air raid alerts remained in effect until after dawn as emergency crews responded to damaged areas and searched for victims.

Russia has intensified ballistic missile attacks on Kyiv in recent months as Ukraine struggles with a shortage of U.S.-made Patriot air defense interceptors. The Patriot system is Ukraine’s primary defense against incoming ballistic missiles.

Zelenskyy has repeatedly appealed to Ukraine’s international partners for additional Patriot interceptors, but global supplies have been strained by demand from Ukraine’s more than four-year war with Russia and the ongoing conflict with Iran.

Zelenskyy described the overnight assault as a carefully prepared operation involving several types of weapons.

“It was a massive attack,” he said, accusing Russia of combining ballistic missiles, cruise missiles and drones in an effort to inflict maximum damage on civilian infrastructure.

The latest barrage underscores the growing pressure on Ukraine’s air defenses as Russia continues its intensified aerial campaign against the capital and other parts of the country.