Russia launched a large-scale missile assault on several Ukrainian regions at the start of peak morning hours on Monday, Ukraine's military officials said, with all of the country under air raid alerts.

"Kyiv - shelter!" Ukraine's Air Force said on the Telegram messaging app, saying the capital was under ballistic missile threat.

Ukraine's military officials in Kryvyi Rih, Zaporizhzhia, Kharkiv, Dnipropetrovsk and Khmelnytskyi have also said their cities were under a "massive missile attack" by Russia.