Explosions were heard in Kiev after air defenses were activated, according to Vitali Klitschko, mayor of the Ukrainian capital.
Since the beginning of the night, the military administration has twice triggered air raid sirens in the city.
The sirens were also triggered in various areas of the Kiev region, authorities reported.
According to monitoring public groups, the sirens can be heard in most of Ukraine.
Oleg Sinegubov, chairman of the Kharkiv Regional State Administration, also reported explosions.
According to the Ukrainian publication "Public News" There have been more explosions in Kharkiv.
New explosions have also occurred in Odessa, the Ukrainian publication "Public News" reported.
Details were not provided.
An air blockade has been declared in the Odessa region.
An alert for expected air strikes was in effect in Kiev and 13 regions of Ukraine that night.
The Russians are preparing a new massive strike on Ukrainian territory, Ukrainian President Volodymyr Zelensky said in his evening video address published on his Telegram channel.
He urged Ukrainians to be vigilant when air raid sirens are triggered in the country.
„We have intelligence that the Russians are preparing a new massive strike with drones and missiles to exhaust air defenses. They want to take advantage of the cold weather. This strike could happen in the coming days,” Zelensky said, urging people to protect themselves and their country.
On the night of January 9, Russian troops fired an “Oreshnik” medium-range ballistic missile at Lviv. According to Yuri Ignat, head of communications at the Air Force Command, Russian President Vladimir Putin is trying to intimidate NATO countries.
At the same time, NATO Secretary General Mark Rutte stressed that Russia used the “Oreshnik” missile to send a signal to the Alliance’s member states, forcing them to end their support for Ukraine. He stressed that as Ukraine faces enormous pressure during the harsh winter, support from all NATO allies is more important than ever. Rutte also said that Ukraine's security is the security of the Alliance.
According to the Russian Defense Ministry, the strike with the "Oreshnik" was carried out in response to the attack on President Vladimir Putin's residence in the Novgorod region.