Tonight escalating tensions between the U.S. and Ukraine, President Trump calling President Zelensky a dictator and blaming Ukraine for the Russian invasion.

The Ukrainian leader slamming him for disinformation.

The rapidly deteriorating relationship between once key allies and what it all means for the war.

A Richard Engel is on the front lines. At least two

killed when a pair of single-engine planes collided in the sky in Arizona. Chard debris left

scattered on the runway, what we're learning about the latest fatal aviation accident.

Elon Musk's Doge employees now working inside the Pentagon, as NBC News reports the Defense Secretary may dismiss top military generals.

The showdown and fallout over mass firings one month into Trump's presidency.

The dangerous winter storm sending temperatures plunging below zero.

Cars out of control in Tennessee, rescues

from freezing water in Virginia, parts of the south, under states of emergency.

Just in, the new ruling in the Idaho College murders the evidence allowed in.

The arrests in a string of burglaries targeting celebrities and pro athletes, including Kansas City Chiefs star Travis Kelsey and Patrick Mahomes.

And there's good news tonight, the mother's son duo making history on the basketball court.

This is NBC Nightly News with Lester Holt.

Good evening and welcome.

The world has been virtually turned upside down in the long-running war between Ukraine and its Russian invaders,

with American President Trump sharply turning against Ukrainian President Zelensky.

In a social media post-Trump labeling Zelensky, who is the democratically elected

leader of Ukraine, a dictator and inaccurately accusing Ukraine of starting the war, which even

Trump's former vice president publicly called out as untrue. The U.S. has spent billions in

military assistance helping Ukraine fight back against the Russian aggressors.

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