WASHINGTON 

The US has delivered more than half of the 90 howitzer artillery guns destined for Ukraine, with more on the way, the Pentagon announced Wednesday.

Spokesman John Kirby told reporters that over 50 Ukrainian fighters completed training on the M777 howitzer weapons earlier this week, with another batch of troops expected to begin training soon if they have not already begun.

All of the trainings have taken place outside of Ukraine.

Asked about Russian nuclear saber rattling, Kirby was adamant that Secretary of Defense Lloyd Austin "remains comfortable that we have the appropriate strategic nuclear deterrent posture in place."

At least 2,787 civilians have been killed and 3,152 others injured in Ukraine since the war started on Feb. 24, according to UN estimates. The true toll is feared to be much higher.

So far, 7.7 million people in Ukraine have been internally displaced, with more than 5.3 million fleeing to other countries, according to the UN refugee agency.