The Kremlin said on Friday the Ukraine war was "existential" for Russia, after it launched a wave of retaliatory drone and missile strikes that killed at least four people.

But halting progress, ever-more deadly drone attacks and unmoving negotiating positions seem to have taken their toll. On Thursday, Trump used a striking analogy to concede the warfare was nowhere near over, and that he did not, at that moment, feel it was best to intervene.

Kremlin calls Ukraine war "existential," launches retaliatory strikes; peace talks stall amid escalating violence.