The leader of of Russia's Wagner mercenary group appeared on Sunday to ditch plans to withdraw his forces from Bakhmut in eastern Ukraine after receiving promises overnight that they would get all the arms needed to capture the devastated city.

Yevgeny Prigozhin said in a new audio message that the Kremlin has promised to resupply his Wagner Private Military Company with as much ammunition and weapons as they need.

Prigozhin said that for the first time he received a response to the situation regarding the shortage of ammunition. He said on Saturday night that the relevant companies promised to deliver everything necessary to continue the offensive in Bakhmut.

"Overnight we received a combat order, for the first time in all this time," Prigozhin said. "We have been promised as much ammunition and weapons as we need to continue further operations. We have been promised that everything needed to prevent the enemy from cutting us off (from supplies) will be deployed on the flank," he added.

In addition, Russian Army Gen. Sergei Surovikin will personally deal with issues of interaction between the Wagner PMC and the Ministry of Defense, Prigozhin said. "This is the only man with the star of an army general who knows how to fight," Prigozhin said of the Russian Defense Ministry assigning Surovikin to work alongside Wagner.

Surovikin commanded Russia's Ukraine campaign for several months before the chief of the General Staff, Army Gen. Valery Gerasimov, was given overall operational command above him.

Russia is ready to use all means at its disposal to prevent anyone from encroaching on the security of the country in response to the recent drone attacks targeting the Kremlin, Russian Deputy Foreign Minister Sergey Ryabkov said in an interview on Russia's Channel One Thursday.

Ryabkov said Washington is using its "puppets" in Kyiv to stage more and more dangerous provocations.

"I think that any reasonable person in any country will understand that the United States continues its escalatory policies and uses its subordinates in Kyiv, their puppets, to stage and carry out more and more audacious, more and more dangerous, acts of provocation," he said.

He went on to say that U.S. officials may deny any responsibility and involvement in the attacks but nobody will believe them.

"We are working to prevent relations with the U.S. from plunging into the abyss of an open armed conflict. We are already standing on the edge, on the edge of this precipice," he said.

Russia’s Wagner mercenary group said it will retreat from Bakhmut because of severe shortages in ammunition, according to Yevgeny Prigozhin, the group's leader. He said his forces would withdraw on May 10, blaming Russia’s defense ministry for the retreat.

Wagner has played a crucial role for months in the fighting for Bakhmut, sustaining huge casualties. The announcement and the suggestion of bitter infighting within Russia’s military forces signals division and disorganization just as Russia is bracing for a major Ukrainian counteroffensive.

Prigozhin said he was taking the decision in retaliation against Russia’s military leadership, which he accused of deliberately starving his troops of ammunition because they are jealous of Wagner’s success.

Prigozhin and Russia’s defense ministry have been in a one-sided public feud for months. Prigozhin claims it's now reached a breaking point, delivering a blistering attack on Russia's senior military command in the video announcing the withdrawal. He accused them of being "cowards" and of denying Russians a victory in Bakhmut because of their "petty envy."

Ukrainian military officials said they did not believe Wagner forces would retreat from Bakhmut, suggesting they believed his announcement was an attempt to excuse his failure to seize the city by May 9 as he pledged. A spokesman for Ukraine's eastern command, Sergiy Cherevatyi, said Wagner was running out of fighters, not ammunition.

-ABC News' Patrick Reevell

Ukrainian President Volodymyr Zelenskyy called for a war crimes tribunal in a surprise visit to The Hague on Thursday.

"There must be accountability for this crime. And this can only be achieved through the tribunal. ... We must transform the experience of the Nuremberg trials into new operational rules. And that is why we advocate the creation of such a tribunal. We want to continue the tradition of mandatory punishment for such crimes as a guarantee of non-repetition of such aggression," Zelenskyy said.

-ABC News' Will Gretsky

A top Russian pro-war blogger has been killed in a bomb attack on a cafe in Russia, according to police.

The explosion on Sunday tore through a cafe in St. Petersburg, killing Vladlen Tatarsky, one of the best-known of the Russian military bloggers who have become influential during the war in Ukraine.

At least 30 other people were injured in the blast, according to the Ministry of Health. Video circulating online appeared to capture the aftermath, showing bloodied people emerging from the heavily damaged cafe.

The Russian Interior Ministry said an explosion has occurred in a cafe on the city's Universitetskaya Embankment.

"One person was killed in the incident, it was military correspondent Vladlen Tatarsky, the Russian Interior Ministry press center told reporters on Sunday.

Denis Pushilin, acting head of the Russian-backed Donetsk People’s Republic, issued a statement describing Tatarsky as "a great patriot" of the Donbass region of eastern Ukraine and Russia. Pushilin blamed the attack on the Kyiv regime, calling it a terrorist regime.

"A man with a difficult fate, Vladlen earned the respect of his comrades-in-arms because he lived and worked for the sake of truth and justice, for the sake of victory," Pushilin said of Tatarsky. "He managed to fight, and in the status of a military correspondent to make his contribution."

Pushilin said Tatarsky was to be awarded a medal "for the liberation of Mariupol" in eastern Ukraine.

It was the most serious bomb attack on a pro-war Russian figure inside Russia since the high-profile assassination of the Daria Dugina, the daughter of the ultra-nationalist Alexander Dugina, who was killed in a car bombing last year.

Tatarsky was a Russian ultra-nationalist and one of the best-known military bloggers, who strongly supported the war in Ukraine. He had also criticized the execution of the war by Russia’s military command.

Tatarsky had become a significant source of information for how the war was being fought on the Russian side.

His killing will likely set off speculation on whether Ukraine or Russia was behind his killing, similar to the Dugina episode.

In the Dugina case, U.S. intelligence sources eventually told The New York Times that Ukraine was behind the attack.

-News Patrick Reevell