Why Russia has suffered the loss of an 'extraordinary' number of generals

Ukraine hss claimed 12 Russian generals have been killed since the invasion began.

During its war in Ukraine, Russia's top military leadership has proven to be particularly vulnerable, experts say.

Ukraine's Ministry of Defense has claimed that 12 Russian generals have been killed since the invasion began in late February.

Russian officials have not confirmed that number. U.S. officials -- who last week pushed back on a New York Times report that said the U.S. provided Ukraine intelligence that helped it target and kill Russian generals and other senior officers -- also have not confirmed the number of Russian generals killed.

Though, as reported by Ukraine, that kind of loss is "quite extraordinary," ABC News contributor and retired Col. Steve Ganyard said.