WASHINGTON (NEXSTAR) — The U.S. continues to monitor the situation as weapons and supplies are sent to Ukraine to fend off Russian forces.

“A nuclear weapon is a nuclear weapon,” Pentagon Press Secretary John Kirby said.

Kirby says Russia is making reckless threats of nuclear war.

“As irresponsible as it is for him to use that rhetoric. It would be equally irresponsible for us, not to take it seriously,” Kirby said.

For now, Kirby says the U.S. sees no reason to change its deterrent strategy and is focused on helping the Ukrainian people defend themselves.

“Training has already occurred outside Ukraine, particularly on the howitzers,” Kirby said.

A Russian missile strike killed at least one person inside Kyiv on Thursday. Kirby says it’s another sign that Russian aggression is unjustified.

“None of them, none of them were threatened by Ukraine. It’s hard to square that rhetoric by what he’s actually doing in Ukraine to innocent people,” Kirby said.

The White House is also concerned Russian President Vladimir Putin still plans to attend the G-20 summit in November.

“The president has expressed publicly his opposition to President Putin attending the G-20. We have welcomed the Ukrainians attending or invitation to attend the G20,” White House Press Secretary Jen Psaki said.

Kirby would not say whether what is happening is genocide.

“It is very clear that Russian forces have committed war crimes, there’s no question about that,” Kirby said.