Ukrainian President Volodymyr Zelenskiy signed a decree on the general mobilization of the population on Thursday night in the wake of Russia's invasion.
The decree stated that mobilization is to be carried out within 90 days.
He also vowed on Friday to stay in Kyiv as his troops battled Russian invaders who are advancing toward the capital in the biggest attack on a European state since World War Two.
CNN reported in the early hours of Friday morning that Russia intended to bomb Kyiv at 3 a.m., according to US intelligence, but that did not happen
The Russian 58th Brigade was held off in the north of Ukraine where battles were being held in the Peremoha regions, while in the south, Ukrainian forces retook a captured bridge near Kherson along the Dnieper river
Moscow captured the Chernobyl nuclear power plant in northern Ukraine on Thursday after Russian troops crossed into the country from Belarus, entering through the Chernobyl nuclear disaster zone, and have now advanced closer to Kyiv, a US defense official said.
People working at the power plant were taken hostage.
Russian forces have also taken over Zmiinyi Island, a Ukrainian island in the Black Sea, Ukraine's National Police said late on Thursday. Ukraine forces are still battling to keep hold of the Gosmotel military airport, near capital Kyiv, as two Russian helicopters were shot down by Ukrainian forces during sustained attacks on Gostomel, Ukraine's Armed Forces said.
57 Ukrainians had been killed and 169 were wounded on the first day of heavy fighting between Russian and Ukrainian forces on several fronts, Ukraine's health minister said. Ukrainian Armed Forces reported a similar number of casualties on the Russian side, adding six Russian planes were downed along with the two helicopters that were shot down in Gostomel.
A Russian Antonov AN-26 military transport aircraft crashed in Russia's Voronezh region on Thursday night, killing the entire crew, Interfax reported citing military officials. Russian military officials have reportedly said the crash could have been caused by a technical failure. The Ukrainian military added that dozens of Russian armored equipment units were destroyed. A Russian platoon of Russia's 74th motor rifles brigade has surrendered to Ukrainian forces near Chernihiv in northern Ukraine, according to the Ukrainian Armed Forces.
Ukrainian president Volodymyr Zelenskiy said prior to the capture of Chernobyl that Ukrainian forces are "giving their lives to prevent the capture of the nuclear disaster zone, as heavy fighting in eastern Ukrainian cities continued after Russian President Vladimir Putin authorized a "special military operation" in the early hours of Thursday morning.
Russian occupation forces are trying to seize the #Chornobyl_NPP. Our defenders are giving their lives so that the tragedy of 1986 will not be repeated. Reported this to @SwedishPM. This is a declaration of war against the whole of Europe.— Володимир Зеленський (@ZelenskyyUa) February 24, 2022
Earlier, four ballistic missiles were launched from the territory of Belarus into Ukraine. The mayor of Ukraine's capital Kyiv ordered a curfew on Thursday in comments shown on television.
Elsewhere, parts of Ukraine's southern Kherson region were no longer under Kyiv's control, the regional administration said. In addition, Russian troops have taken over the Kakhovka hydroelectric power station built on the Dnieper River, Ukraine's energy minister said. The outskirts of Ukraine's port city of Mariupol came under heavy fire and hundreds of explosions have been observed there, a diplomatic source told Reuters on Thursday, as Ukrainian forces battled Russian invaders on three sides.
Zelenskiy said Ukraine was listening to the sound of a new iron curtain falling as Russian troops advanced across his country's territory and he warned that other European countries may be next.
Russia carried out over 203 attacks on east Ukrainian cities on Thursday alone, Ukrainian police said moments before four Ukrainians were killed as Russian forces hit a hospital in Ukraine's Donetsk region, according to local Ukrainian leadership. In addition, Russian forces have reportedly taken a prisoner during the heavy fighting in the east, the Ukrainian deputy defense minister said after two Russian soldiers were captured by Ukraine's Armed Forces.
A series of loud blasts were heard in Russia's southern Belgorod region, near the Ukrainian border, on Thursday due to what a Russian investigative committee concluded to be shelling from Ukrainian forces. Three were injured in the reported attack in Belgorod, according to the investigative committee.
Israeli intelligence firm ImageSat Intl. released on Thursday satellite images showing Russian forces in Belgorod. It is reported that Belgorod is one of Russia's main routes of invasion to Kharkiv, Ukraine's second-largest city.
#ISI reveals: #Russian military forces in #Belgorod.Supporting one of the main Russian military invasion efforts towards the city of #Kharkiv (Second largest city in #Ukraine). pic.twitter.com/1CCLRsFq9G— ImageSat Intl. (@ImageSatIntl) February 24, 2022
Soon after Putin announced the operation in Ukraine's Donbas region, a series of explosions could be heard in Kharkiv and the capital Kyiv, which were attacked with a barrage of missile strikes. Later, black smoke was seen rising over the Ukrainian Defense Ministry's intelligence headquarters in central Kyiv.
Some 74 "above-ground military infrastructure objects" in Ukraine were destroyed on Thursday, Russia's Defense Ministry announced.
While Russia claimed its airstrikes were not targeting cities and posed no threat to civilians, sirens sounded in Kyiv, Lviv and at a border crossing between Poland and Ukraine. Ukrainian Armed Forces stated that Russia conducted strikes on a number of both civilians and military locations, adding that Ukrainian forces are combating Russian ones as they break through the border.
In the Sea of Azov, two civilian ships were hit by Ukrainian missiles, with casualties reported by Russian media after Russia restricted the movement of commercial vessels in the sea until further notice.
A Turkish-owned vessel was the unintended target of a bomb off the coast of Odessa, Turkey's Maritime Authority said on Thursday. The ship is safe and no casualties were reported in the incident.
Reuters contributed to this report.