Russia-Ukraine updates: Putin says war was ‘unleashed’ on Russia

A Russian missile airstrike was reported in different areas of Ukraine Sunday evening.

Sixteen Russian Tu-95 bombers were reported in the air from various airfields and explosions were reported in the Dnipropetrovsk region of Ukraine at 10:51 p.m. local time.

“Presumably, Kh-101 cruise missiles are actively flying at the Pavlograd-1 and Pavlograd-2 railway stations, where trains with APU (Ukrainian Armed Forces) equipment and people were located,” a Russian Telegram channel, Military Chronicle, said.

Several explosions were heard in the city of Pavlograd, in the Dnipropetrovsk region, local Ukrainian media reported.

An air alert was announced for the region at 9:30 p.m. local time and about 10:00 p.m., social networks began to report explosions in Pavlograd.

According to local media, repeated explosions were heard in the city at 10:20 p.m.

The strikes destroyed Ukrainian anti-aircraft missiles for the S-300 complex on Pavlograd, Russian Telegram channel Intel Slava reported.

S-300s are long-range surface-to-air missiles.

Supply vehicles with reserve ammunition that belong to the Ukrainian Armed Forces were also hit, the channel said, citing eyewitness accounts.

Intel Slava is funded by the Russian government.

“The detonation of rockets has been going on for almost an hour,” the Intel Slava post said.

It's unclear how many people were injured or killed.

-ABC News' Fidel Pavlenko and Anastasia Bagaeva

The Russian oligarch behind the Wagner private paramilitary group fighting for the Kremlin in Ukraine is threatening a mutiny if his forces are not resupplied with ammunition soon.

Yevgeny Prigozhin, owner and curator of the Wagner group, penned a letter to Russian Defense Minister Sergei Shoigue, demanding ammunition be provided to his forces on the battlefield.

In the letter, Prigozhin wrote that if supply problems are not fixed fast, he will complain to Russian President Vladimir Putin and his mercenaries would abandon their positions in Bakhmut, Ukraine, where heavy fighting has been going on for weeks, The Moscow Times reported.

“I appeal to Shoigu with a request to immediately issue ammunition. In case of refusal, I consider it necessary to convey to the Supreme Commander-in-Chief information about the existing problem in order to make a decision and about the advisability of further presence of Wagner PMC in Bakhmut in the conditions of a shortage of ammunition," Prigozhin wrote.

He added, "If the deficit is not replenished ... we will be forced to withdraw part of the units from this territory, and then everything else will crumble. Therefore, the bell is already ringing -- it is called an alarm."

Emphasizing the urgency, Prigozhin noted that Ukraine is planning to launch a counteroffensive soon.

There was no immediate public response from Shoigu or the Kremlin.

"We need to stop deceiving the population and telling that everything is fine with us," Prigozhin wrote. "I must honestly say: Russia is on the brink of disaster. If these screws are not adjusted today, the 'aircraft' will crumble in the air."

Ukrainian President Volodymyr Zelenskyy on Sunday wished Ukrainian military forces success in what he described as the "main battles" that are "coming soon."

Zelenskyy's statement came a day after he said at a news conference in Kyiv that Ukrainian forces will soon launch a counteroffensive, likely before F-16 fighter jets promised by Western allies arrive.

"Dear warriors, the main battles are coming soon. We must free our land and our people from Russian slavery,” Zelenskyy said at an event where he bestowed medals to members of the county’s Border Guard forces.

Ukrainian President Volodymyr Zelenskyy said the Ukrainian counteroffensive will start before Ukraine receives F-16 fighter jets sought from Western countries.

"Frankly speaking, it would help us a lot. But we also understand that we can't drag it [the counteroffensive] out, which is why we'll start before we receive F-16 [aircrafts] or other models," Zelenskyy said at a news conference for Scandinavian media held in Kyiv on Saturday, according to a script provided by Reuters.

He added, "But to calm Russia down with the fact that we'd still need a couple of months to train on the aircrafts and only then we'd start; No, this won't happen. We'll start and go forward, while at the same time, simultaneously, I think this is very important [to receive western fighter aircrafts.]"

He said Ukraine is "capable of putting an end to this war."

Also on Saturday, Ukraine's Foreign Minister Dmytro Kuleba said Ukraine received a signal from some countries about the readiness to start training Ukrainian pilots on F-16 fighter jets.

According to Kuleba, the F-16 fighter jet is the ideal aircraft due to its technical characteristics, although Kyiv does not overlook other aircraft, either. The minister added that the decisive word on issuing F-16s will be with the United States, because these are American fighters.

-ABC News' Edward Szekeres and Max Uzol