In light of the presumed death of Wagner Group leader Yevgeny Prigozhin, the Russian Volunteer Corps, a group of Russians fighting alongside the Ukrainian Armed Forces, released a video appealing to the PMC's members.

The statement offered them "a difficult but rather logical choice: either subjugate themselves to the Russian Ministry of Defense in the service of the killers of their commanders, or save their honor and take revenge on their executioners, going over to the side of Ukraine."

"If you have not committed war crimes on the territory of Ukraine, then we invite you to join our ranks," the statement said.

The wider Ukrainian military has not commented on the offer or whether any theoretical defections would in fact be supported.

-ABC News' Will Gretsky

Beginning in October, the U.S. will provide F-16 training to a small number of Ukrainian pilots and maintenance teams, Pentagon press secretary Brig. Gen. Pat Ryder said Thursday.

Ryder said "several" pilots and "dozens" of aircraft maintenance personnel will begin training at Morris Air National Guard Base in Tucson, Arizona, after they receive English training in September at Lackland AFB in San Antonio, Texas. The number of pilots and personnel will be determined by Ukraine.

"Although some Ukrainian pilots have English language skills we are anticipating that all the pilots coming to the United States will require some level of additional English language instruction, given the complexities and the specialized English that's required to fly these aircraft," said Ryder.

Sabrina Singh, the Pentagon's deputy press secretary, told reporters earlier this week that the U.S. was open to the idea of training on F-16's if European countries reached capacity though she couldn't define what numbers would constitute capacity. Ryder on Thursday also wouldn't provide a number and said the U.S. wasn't going to wait for the Netherlands and Denmark to reach capacity.

"We know that as the Danes and the Dutch prepare to train those pilots that at a certain point in time in the future, capacity will be reached. So preemptively acknowledging that and leaning forward in order to to assist with this effort is the impetus for why we're doing this now," said Ryder.

Ryder wouldn't get into when F-16 deliveries to Ukraine might begin. Denmark's Prime Minister said over the weekend that the first Danish F-16's could arrive by New Year's.

-ABC News' Luis Martinez

Wagner Group leader Yevgency Prigozhin was "likely" killed in a plane crash near Kuzhenkino, Russia, on Wednesday, the Pentagon said.

Pentagon press secretary Brig. Gen. Pat Ryder said there is no information to suggest a surface-to-air missile brought down the plane. Nine others, including Wagner's co-founder, Dmitry Utkin, are also presumed dead.

"We don't have any information to indicate right now ... there was some type of surface to air missile that took down the plane ... we assessed that information to be inaccurate," Ryder said.

He added, "But beyond that, I'm really just not going to have any further information. What was it, something that came ... from inside the plane? Again, I don't have any additional insight to provide on that."

-ABC News’ Luis Martinez

Russian President Vladimir Putin offered his first comments Thursday on the plane crash that presumably killed Wagner Group head Yevgeny Prigozhin and the private military company's co-founder Dmitry Utkin along with eight others near Kuzhenkino, Russia, on Wednesday.

"As for the aviation tragedy, first of all, I want to express my sincerest condolences to the families of all the victims," Putin said in an on-camera address, adding that Wagner Group made a "significant contribution to our common cause of fighting the neo-Nazi regime in Ukraine."

"I knew (Yevgeny) Prigozhin for a very long time, since the early 1990s. He was a man with a complex destiny, and he made serious mistakes in life," Putin said. "He achieved the results he needed both for himself and, when I asked him, for the common cause, as in these last months."

Putin said of the investigation, "But what is absolutely clear -- the head of the Investigative Committee reported to me this morning, they have already launched a preliminary investigation into this incident. And it will be carried out in full and to the end. There is no doubt about that here. Let's see what the investigators say in the near future. Tests -- technical and genetic tests -- are being carried out now. This takes some time."

-ABC News’ Will Gretsky