Russian forces were on Thursday trying to encircle Kiev amid intense fighting currently underway within 20-40 km of the Ukrainian capital, a non-profit think tank said.
In a statement to the local Ukrainska Pravda newspaper, the Kiev-based Centre for Defence Strategies said: "The enemy is trying to encircle the capital with a massive gathering of troops (close to 30 tactical battalions). The biggest threat comes from the north and north west of Kiev (Ivankiv, Vorzel, Bucha, Irpin Hostomil)."
The statement further said that 'ntense fighting continues within 20-40 km of Kiev, "where the enemy is losing equipment and personnel".
The think tank said it is expected that within a short time the Russian forces will attempt to enter Kiev with the help of the air force and missile attacks.
Meanwhile in the west of Kiev, Ukrainian Armed Forces have freed the town of Makariv and established defensive positions, Ukrainska Pravda reported.
In addition to Kiev, priority targets for the Russians include large cities in Ukraine's south and Kharkiv.
Earlier in the day, the Ukrainian Defence Ministry on Thursday announced that Russian ships and rocket boats were approaching the country's third largest city of Odessa located on the northwestern shore of the Black Sea.
"In the waters of the Black Sea, we are observing a landing detachment of the Russian Black Sea Fleet, consisting of four large landing ships accompanied by three rocket boats, advancing towards Odessa," the Ministry said in a statement.
While Wednesday night passed peacefully for several regions of Ukraine, Russia on Thursday continued to attack Kharkiv, Severodonetsk and Lysychansk.
The Mayor of Kherson city claimed early Thursday morning that Russian forces have seized the city.
According to Ukrainska Pravda, Ukrainian troops have continued to defend Chernihiv and Nizhyn, but the situation in the Vyshhorod area just outside of Kiev is tense.
The night in the Donetsk region was difficult, but Mariupol held.