This handout video grab taken and released by the Ukraine Presidency press service on February 28, 2022 shows Ukrainian President Volodymyr Zelensky delivering an address in Kiev. (Photo: AFP)

KIEV, Feb. 28 (Xinhua) - The next 24 hours will be crucial for Ukraine's fight with Russia, said Ukrainian President Volodymyr Zelensky on Monday during a phone conversation with British Prime Minister Boris Johnson, the National News Agency of Ukraine (Ukrinform) reported.

Johnson said he would do all he could to help ensure defensive aid from Britain and other allies reached Ukraine.

Meanwhile, according to the regional government, the city Berdyansk in southern Ukraine had been seized by Russian troops Monday morning.

The Ukrainian army said on Monday that the situation in Kiev was still under its control.

According to the latest development, a Ukrainian delegation arrived at the place for talks with the Russian side in the Gomel region in Belarus on Monday, Sputnik reported.