Kyiv - Russian troops have entered Ukraine's second city Kharkiv and fighting was under way on Sunday, the head of the regional administration said on the fourth day of Moscow's invasion of the pro-Western country.
"The Russian enemy's light vehicles broke into the city of Kharkiv," Oleg Sinegubov said in a Facebook post, urging residents not to leave shelters.
"The Ukrainian armed forces are eliminating the enemy."
While fighting raged in Kharkiv, the city administration in Kyiv, 400 kilometres (250 miles) to the west, said the capital remained completely under the control of Ukrainian forces despite clashes with "sabotage groups".
The Russian defence ministry claimed on Sunday that its troops had besieged the southern Ukrainian city of Kherson and the city of Berdyansk in the southeast.
"Over the past 24 hours, the cities of Kherson and Berdyansk have been completely blocked by the Russian armed forces," defence ministry spokesman Igor Konashenkov said in a statement.
He added that Russian troops had also taken control of Genichesk, a port city along the Sea of Azov, and an airfield near Kherson.
As of Sunday, the Russian army said it had destroyed 975 military facilities in Ukraine and shot down eight fighter jets, seven helicopters and 11 drones.
Konashenkov claimed that Ukrainian servicemen were laying down arms "en masse."
He claimed that on Saturday forces of an air defence missile regiment near Kharkiv "voluntarily" put down their arms, adding that more than 470 Ukrainian servicemen had been detained.
There was no independent verification of any of these claims and Ukraine insists it has inflicted heavy casualties on the Kremlin's forces.
Russian President Vladimir Putin on Thursday ordered the invasion of Ukraine. Russian ground forces have pressed into Ukraine from the north, east and south but have encountered fierce resistance from Ukrainian troops, the intensity of which has likely surprised Moscow, according to Western sources.
On Saturday, Moscow ordered its troops to advance in Ukraine "from all directions", with the Kremlin claiming Ukrainian authorities have refused to hold talks.
AFP