Russia pounded Ukraine's capital of Kyiv with missiles early on Monday, with its mayor saying emergency services were sent to several districts following reports of damage and injuries from falling debris from the downed weapons.

All of Ukraine was under air raid alerts, while neighbouring NATO member Poland activated Polish and allied aircraft to ensure the safety of its airspace.

On the Telegram messaging app, Ukraine's air force said repeated launches of ballistic missiles targeted Kyiv, while city officials said air defence units were repelling the attacks.

Fire broke out in the Shevchenkivskyi district, where medics were attending to at least one person, the capital's Mayor Vitali Klitschko said on Telegram. The district is home to a cluster of universities and schools.

Emergency services also went to the districts of Svyatoshynksyi, Holosiivskyi, and Solomyanskyi, he added.

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 its southwest.

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.

The attack came exactly a week after Moscow launched more than 200 missiles and drones on Ukraine, killing seven people and striking energy facilities nationwide in what Kyiv called the war's "most massive" attack. (Reporting by Pavel Polityuk and Valentyn Ogirenko in Kyiv; Writing by Lidia Kelly in Melbourne; Editing by Muralikumar Anantharaman and Clarence Fernandez)