Russian forces surrounded the cities across Ukraine Sunday morning, blocking civilians from fleeing the violence and firing on civilian targets.

Russia continued its bombardment of various cities, launching airstrikes stepping up shelling outside of the capital city Kyiv.

Air raid alarms echoed again in nearly every region of Ukraine, according to local reports.

Russian aircraft fired eight missiles that hit the Yaroviv International Peacekeeping and Security Center near the city of Lviv, just 10 miles from the Polish border around 6 a.m. local time Sunday, Ukrainian officials said on Sunday.

The IPSC is a massive military base that includes a training center for soldiers, mainly for peacekeeping missions, that has been supported by the United States in the past.

In the strategic port city of Mariupol in Ukraine’s south –  which has been devastated by incessant Russian bombings – efforts to deliver food, water and medicine into the city of 430,000 people was prevented by another day of brutal shelling Saturday.

More than 1,500 people have died in Mariupol during the siege, according to the mayor’s office, which said the shelling has even interrupted efforts to bury the dead in mass graves. 

Talks between Ukrainian and Russian officials attempting to reach a cease-fire agreement fell apart again on Saturday.

The US has pledged to send an additional $200 million in weapons but Russia issued a stern warning to the U.S. and its allies that transports of weapons to Ukraine will be considered “legitimate targets” for Russian forces. 

French and German leaders spoke Saturday with Russian President Vladimir Putin in a failed attempt to reach a cease-fire, during which Putin laid out his conditions for ending the fighting: Ukraine must drop its bid to join NATO and adopt a neutral status; acknowledge Russian sovereignty over Crimea; recognize the independence of the Russian controlled regions of Luhansk and Donetsk; and to demilitarize.

Ukraine President Voloymyr Zelensky has accused Russia of starting “a new stage of terror” and compared Russian soldiers to “ISIS terrorists” after they abducted the mayor of the city of Melitopol on Friday.

“Ukraine will stand this test. We need time and strength to break the war machine that has come to our land,” Zelensky said during his nightly address on Saturday.

Get the latest updates in the Russia-Ukraine conflict with The Post’s live coverage.

Zelensky said Russia would need to carpet-bomb Kyiv and kill its residents to take the city, ahead of an anticipated all-out assault on the capital as Russian forces attempt to encircle it. So far, about 2 million people have fled the city, according to the president.

“They will come here only if they kill us all,” he said. “If that is their goal, let them come.”

A convoy of hundreds of people fleeing Peremoha, a suburb about 12 miles northeast of Kyiv, were forced to turn back under shelling by Russian forces that killed seven people, including a child, Ukraine’s defense ministry claimed Saturday. 

Moscow has said it would establish humanitarian corridors to evacuate civilians out of conflict zones, but Ukrainian officials have accused Russia of disrupting those paths and firing on civilians.

Ukraine’s Deputy Prime Minister Iryna Vereshchuk said just nine of 14 agreed-upon corridors were open on Saturday, and that about 13,000 people had used them to evacuate around the country.

Russian soldiers pillaged a humanitarian convoy that was trying to reach Mariupol and blocked another, a Ukrainian official said. Russian forces are now in control of the eastern outskirts of the city as they escalate their siege on the port in an effort to establish a land corridor to Crimea, which it seized from Ukraine in 2014.

Mariupol has been without water or electricity for over a week. Aid group Doctors Without Borders said residents are dying from a lack of medication and are draining heating pipes for drinking water.

In Irpin, a suburb about 12 miles northwest of central Kyiv, bodies lay out in the open on streets and in a park on Saturday.

Zelensky tried to rally his people to keep up their resistance against Russian invaders. “We do not have the right to let up our defense, no matter how difficult it may be,” he said.

On Saturday,  Zelensky reported that 1,300 Ukrainian soldiers had died since the Russian invasion began 17 days ago on Feb. 24.

Thousands of civilians have been killed, including at least 79 Ukrainian children, Ukraine’s government says. At least 2.5 million people have fled the country, according to the United Nations refugee agency, over 1.5 million who have crossed into Poland.

Russian forces have hit at least two dozen hospitals and medical facilities, according to the World Health Organization.

The Russian invaders appear to have struggled far more than expected against the fierce defense of embattled Ukrainian fighters, however their outgunned and outnumbered forces could be worn down by the ceaseless Russia assaults.

With Post wires