KYIV, Ukraine -- Russia launched a major offensive into eastern Ukraine on Monday, authorities in Kyiv said, as Moscow opened a new phase of its invasion after being thwarted in efforts to capture the capital.
In recent weeks, Russia's military campaign has refocused on the eastern region of Donbas, which pro-Moscow separatists have partly controlled since 2014.
"We can now confirm that Russian troops have begun the battle for the Donbas, which they have been preparing for a long time," Ukrainian President Volodymyr Zelensky said on Telegram late Monday.
"No matter how many Russian soldiers are brought here, we will fight. We will defend ourselves."
Ahead of the widely anticipated advance, Ukrainian authorities had urged people in Donbas to flee west to escape.
Control of Donbas would allow Moscow to create a southern corridor to the occupied Crimean peninsula.
In the south of Donbas, Russia continued its push to capture the besieged port city of Mariupol, where the last remaining Ukrainian forces have taken a final stand.
Russia on Monday also pounded targets across the country, killing at least seven people in the far western city of Lviv.
Lviv has largely been spared bombardment since Russia invaded on February 24, and the city and its surroundings had become a relatively safe haven for those seeking safety for the war zone.
But "today we understood clearly that we don't have any safe places in Ukraine. It's very dangerous," a bank employee who gave her name as Natalia told AFP after the strikes.
- Strikes across Ukraine -
Russia's defence ministry said Monday it had hit 16 military targets across Ukraine.
Among the sites struck was a depot near Lviv that Moscow said held weapons recently delivered to Ukraine from the United States and Europe.
Shipments of the latest $800-million US military aid package, which includes helicopters, howitzers and armoured personnel carriers, have arrived at Ukraine's borders, a Pentagon official said Monday.
Shortly before Zelensky's address, the regional governor of the Lugansk region Sergiy Gaiday also announced the beginning of Russia's much-anticipated attack.
"It's hell. The offensive has begun, the one we've been talking about for weeks. There's constant fighting in Rubizhne and Popasna, fighting in other peaceful cities," he said on Facebook.
Russian shelling killed at least eight civilians in eastern Ukraine, according to local authorities.
Gaiday said four people died as they tried to flee the city of Kreminna in Lugansk as Russian troops moved in.
"The Russian army has already entered there, with a huge amount of military hardware... Our defenders have retreated to new positions," Gaiday said in a statement on social media.
But Ukrainian presidential advisor Oleksiy Arestovich said Russian forces had not conquered the city.
Ukraine officials on Monday halted the evacuation of civilians from frontline towns and cities in the east for a second day, accusing Russian forces of having blocked and shelled escape routes.
- War crimes -
President Vladimir Putin has said he launched the military operation on February 24 to save Russian-speakers in Ukraine from a "genocide" carried out by a "neo-Nazi" regime.
He recognised the independence of two self-proclaimed separatist republics in Donetsk and Lugansk shortly before the invasion began.
On Monday, Putin lauded the 64th Motor Rifle Brigade -- which is accused of committing atrocities near Kyiv -- bestowing battle honours on them for "heroism and valour, tenacity and courage".
Ukraine has alleged the brigade is guilty of war crimes while occupying the suburb of Bucha on the outskirts of Kyiv, where residents were shot dead, some with their hands bound.
The European Union condemned Russia's "indiscriminate" bombing of Ukrainian civilians following the strikes on Lviv.
Its foreign policy chief Josep Borrell pointed to "particularly heavy attacks" in eastern and southern Ukraine and an offensive against second city Kharkiv, where officials said Russian shelling killed three people.
"Attacks on Lviv and other cities in western Ukraine show that no part of the country is spared from the Kremlin's senseless onslaught," Borrell added.
Seeking to strengthen ties and accelerate admission to the 27-nation bloc, Zelensky said that Ukraine hoped to receive EU candidate country status within weeks.
On Monday, he handed the EU's envoy to Kyiv a two-volume response to a membership questionnaire brought by European Commission chief Ursula von der Leyen in March.