Reuters/KYIV According to Vitali Klitschko, the mayor of the Ukrainian capital, Russia launched an air attack on Kyiv, and air defense systems were tasked with fending off the strikes early on Sunday.

Klitschko posted on the messaging service Telegram, "Air raid alert continues, air defence units operating."

Witnesses for Reuters claimed to have heard at least two explosions that sounded like they were coming from air defense systems.

Kyiv, its surrounding region and all of eastern Ukraine were under air raid alerts with threat of ballistic weapons being launched at the country, Ukraine's air force said on Telegram

(Reporting by Velentyn Ogirenko and Oleksandr Kozhukhar in Kyiv; Writing by Lidia Kelly in Melbourne; Editing by Sandra Maler)