Russian Foreign Minister Sergey Lavrov "diverted" U.S. Secretary of State Antony Blinken's calls to reconsider the decision to suspend Russia's participation in the New START treaty, Russia's foreign ministry told Interfax, Russian news agency.

“If they want to return to diplomacy, let them return. If they are engaged in self-promotion and such inexpensive PR, well, this is possible. True, the result will be appropriate," Maria Zakharova, a spokesperson for the ministry, told Russian TV channel Rossiya-1.

-ABC News' Natalia Shumskaia

U.S. Secretary of State Antony Blinken and Russian Foreign Minister Sergey Lavrov had an "on the go" talk during the G-20 Meeting of Foreign Ministers in India, but there were no negotiations, Russian Foreign Ministry spokeswoman Maria Zakharova told TASS, a Russian news agency, Thursday.

"Blinken asked for a contact with Lavrov. Sergey Viktorovich [Lavrov] had communication on the go during the second session. But there were no negotiations, no meeting or so on," the diplomat said.

Blinken had said earlier in the day during a press conference he had "spoke briefly" with Lavrov and discussed ending the war, as well as Russia rejoining the New START Treaty on nuclear arms.

"I told the foreign minister what I and so many others said last week at the United Nations and what so many G-20 foreign ministers said today: End this war of aggression, engage in meaningful diplomacy that could produce a just and durable peace," he said. "The United States stands ready to support Ukraine through diplomacy to end the war on this basis."

A senior State Department official downplayed any hopes that the conversation moved the needle on any of the topics.

-ABC News' Tanya Stukalova and Shannon Crawford

Ukraine has shot down 80% of Russian missiles, according to Commander of the Joint Forces of the Ukrainian Air Force Serhiy Nayev.

Nayev made the assessment in a Facebook post on Wednesday about the effectiveness of the air defense system.

"The enemy is also changing his tactics and ways of using air strike means, so we test after every hit," he wrote. "This analysis proves that commanders, respectively, make decisions that ensure the durability of the air defense is at the highest level."

-ABC News' Ellie Kaufman

Colonel-General Oleksandr Syrsky, the commander of Ukraine's Eastern Group of Forces, will send additional units to Bahkmut, according to Ukraine's Deputy Defense Minister Hanna Malyar.

"Bakhmut has been the epicenter of hostilities for several months now. The enemy has concentrated its key efforts there because it aims to reach the borders of the Donetsk region. The situation there is really tense and difficult," Malyar said.

Ukrainian President Volodymyr Zelenskyy echoed that statement in his nightly address.

"The most difficult situation is still Bakhmut and the battles that are important for the defense of the city," he said.

-ABC News' Ellie Kaufman and Will Gretsky

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."