Russia-Ukraine updates: US to ban Russian carriers from its airspace

About 40 to 50% of Russia’s troops are in “attack positions” near the border with Ukraine, a U.S. official told ABC News.

There are about 150,000 troops on the border area, including 125 battalion tactical groups, or BTGs, the official said. 

These BTGs number between 750 and 1,000 personnel each and are specifically outfitted as combat forces. The forces include every capability needed to conduct a combat operation, according to the official.

-ABC News' Luis Martinez

U.S. Defense Secretary Lloyd Austin told ABC "This Week" co-anchor Martha Raddatz that Russian President Vladimir Putin has a number of options available to him and could attack Ukraine in short order.

"This is not a bluff," he said in the exclusive interview.

"I think he's assembled the right kinds of things that you would need to conduct a successful invasion," Austin added.

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EXCLUSIVE: Defense Secretary Lloyd Austin says he doesn't think Putin is bluffingMore from the interview will air on a special edition of "This Week with George Stephanopoulos" on Sunday.

ABCNews.com

Raddatz's full interview with Austin airs Sunday on a special edition of "This Week" from Lviv, Ukraine.

Homeland security and FBI officials in the last few days have quietly been briefing private industry and government officials to shore up and focus on cybersecurity in anticipation of a possible Russian invasion, law enforcement sources told ABC News.

On Thursday, senior law enforcement and homeland officials briefed U.S. banking leaders and on Friday they briefed some of the nation’s governors to take action and get the word out, the source said.

DHS and FBI officials urged state officials to shore up their cyber infrastructure, according to the source.

-ABC News' Luke Barr, Alex Malin and Pierre Thomas

Vyacheslav Volodin, the speaker of Russia’s parliament and a key ally of Vladimir Putin, accused Ukrainian President president Volodymyr Zelenskyy of "provoking the start of a large war,"
in a social media post.

Volodin accused the Ukrainian president of "firing on peaceful citizens," without any evidence.

"Russia doesn’t want war. It has said there many times before and our President Vladimir Putin is saying it today. But if a threat arises to the lives of Russian citizens and compatriots...our country will rise to their defense,” Volodin wrote on his personal Telegram channel.

Volodin also accused the U.S. of laying the groundwork for an attack on Russian-backed separatists by increasing its rhetoric against Russia.

-ABC News' Patrick Reevell