Austin on potential Russian invasion into Ukraine: 'I don't believe it's a bluff'

Defense Secretary Lloyd Austin said he doesn't think Russian President Vladimir Putin is bluffing.

ABC News chief global affairs correspondent Martha Raddatz asked Austin in an interview, an excerpt of which was posted Friday, about the possibility of a Russian invasion of Ukraine due to the buildup of Russian troops along the border.

"This is not a bluff?" Raddatz asked Austin.

"Again, I don't believe it's a bluff. I think he's assembled the right kind of - the kinds of things that you would need to conduct a successful invasion," Austin said.

Raddatz noted that Russians had set up medical tents and had nurses on hand, which she added would not normally indicate a pullback of troops.

"Exactly. If they were redeploying to garrison, we wouldn't be seeing the kinds of things in terms of, not only combat power, but also logistical support, medical support, combat aviation that we've seen in the region," Austin replied.

The full interview with Austin will air Sunday on ABC.

President Biden said earlier Friday he was "convinced" Putin had decided to invade Ukraine. However, the president said that the U.S. was open to diplomacy should Russia opt for the alternative option.

"The entire free world is united," Biden said. "Russia has a choice between war and all the suffering it will bring, or diplomacy."

U.S. envoy to the Organization for Security and Co-operation in Europe Michael Carpenter said the organization had found evidence that up to 190,000 Russian troops are near the Ukrainian border, a stark increase from the approximately 100,000 believed to be there on Jan. 30.

Russia earlier this week claimed that it had pulled back some of its troops near Ukraine, though officials from the U.S. and NATO say Russia appears to only be doing the opposite of that.