KYIV -Loud explosions rocked Ukraine's capital Kyiv early on Monday as Russia launched a barrage of missiles, sparking fires and damaging homes and infrastructure, officials said.

The air force said it had destroyed 22 out of 35 missiles and 20 out of 23 attack drones. Those included nine ballistic missiles and 13 cruise missiles in the Kyiv, Kharkiv, Dnipro, Poltava, Mykolaiv and Zaporizhzhia regions.

Air raid alerts sounded across Ukraine for nearly two hours before the air force declared the skies clear at 6:30 a.m. (0330 GMT). Neighbouring NATO member Poland activated Polish and allied aircraft to keep its airspace safe during the attacks.

The broad bombardment, a week after Russia unleashed its largest air attack on Ukraine since full-scale war began early in 2022, coincided with the first day back at school for many children.

"It was supposed to be school today," said Alina, standing in the courtyard of a school. "We were asleep and woke up to a bang," said her friend Amina.

A boiler house at a Kyiv water plant was partially damaged, as was the entrance to a metro station doubling as a bomb shelter in Svyatoshynksyi district, Kyiv Mayor Vitali Klitschko said on Telegram, although the station was still operating.

The district is home to a cluster of universities and schools.

The attack injured at least two people, Klitschko said. Cars were set ablaze across the city as well as at a non-residential building in the Shevchenkivskyi district, he added.

Emergency services rushed to several locations, including the Svyatoshynksyi, Solomyanskyi and Holosiivskyi districts, where debris had fallen from destroyed missiles.

Solomyanskyi is home to a major train station and Kyiv's main airport. The historic neighbourhood of Svyatoshynksyi is on the city's western edge, while Holosiivskyi is in the southwest.

An Islamic centre was badly damaged in the attack, Crimean Tatar leader Refat Chubarov said on Telegram.

Reuters witnesses in Kyiv heard a series of loud explosions in what sounded like the work of air defence units, some in the central area.

Last Monday, Russia fired more than 200 missiles and drones at Ukraine, killing seven people and striking energy facilities nationwide in what Kyiv called the war's "most massive" attack.

Russia denies targeting civilians in the 30-month-old war.