Biden says U.S. has reason to believe Russia has decided to invade Ukraine

President Biden said Friday that the U.S. has reason to believe that Russian President Vladimir Putin has made the decision to invade Ukraine.

"As of this moment, I'm convinced he's made the decision," the president told reporters at the White House. "We have reason to believe that."

The president delivered brief remarks on Ukraine and answered a few questions from reporters Friday afternoon, following a call with Transatlantic leaders about the likelihood of further Russian aggression against Ukraine. Mr. Biden said the U.S. has "reason to believe the Russian forces are planning to and intend to attack Ukraine in the coming week — in the coming days."

"To be clear, you are convinced — you are convinced that President Putin is going to invade Ukraine, is that what you just said a few moments ago?" CBS News senior White House correspondent Weijia Jiang asked. 

"Yes, I did. Yes," he responded. 

Still, the president said that diplomacy remains an option: up until Russia actually invades Ukraine, "diplomacy is always a possibility," Mr. Biden said. 

The president's remarks came on the heels of the confirmation by U.S. officials that they believe Russia was responsible for cyberattacks on Ukraine that began this week. Mr. Biden said the U.S. also believes Putin will target Kyiv, the Ukrainian capital, which is home to 2.8 million people. 

"We're calling out Russia's plans loudly and repeatedly, not because we want a conflict, but because we are doing everything in our power to remove any reason that Russia may give to justify invading Ukraine and prevent them from moving," Mr. Biden said Friday. "Make no mistake. If Russia pursues its plans, it will be responsible for a catastrophic and needless war of choice. The United States and our allies are prepared to defend every inch of NATO territory from any threat to our collective security as well."

According to a defense official, 40-50% of the 150,000 Russian forces arrayed around the Ukrainian border are now in their "attack positions." This means they are in their assault formations, anywhere from 5-30 miles from the border just waiting for the order to go. In all, there are 120-125 battalion tactical groups, and the official says the destabilization phase of the operation has begun.

A full-scale invasion would be likely to begin with cyber attacks and electronic warfare to take down Ukraine's command-and-control network. This would be followed by air and missile strikes to destroy their key leadership installations. There could be commando raids to assassinate senior government leaders and to seize TV and radio stations. Airborne operations would seize air fields and bridges. Then, the forces at the border would come rolling across in tanks and vehicles to take down the country. Major cities, including the capital of Kyiv, would be targets. The Ukrainian military would try to fight, but they would be quickly reduced to pockets of resistance and last perhaps 10-15 days.

The Biden administration has been urging Americans in Ukraine to leave as soon as possible, warning that the U.S. won't send in troops to rescue them if Russia attacks. 

The president also  disputed Russian claims of genocide and aggressive actions on the part of Ukraine. It defies "basic logic" that Ukraine would try to escalate a conflict, the president said. 

"All these are consistent with the playbook the Russians have used before — to set up a false justification to act against Ukraine," he said. 

— CBS News' Weijia Jiang contributed to this report.