Briefing in brief: US commitment to NATO 'ironclad'

White House press secretary Jen Psaki briefed reporters for about 35 minutes on Tuesday, fielding questions on a range of topics, including the Russia-Ukraine crisis and controversy over President Biden's use of an expletive in an exchange with a Fox News reporter.

Here's the White House briefing - in brief.

US commitment to NATO 'ironclad'

Psaki called the Russians the aggressors after the Kremlin accused the U.S. of escalating tensions by placing 8,500 of troops on heightened alert to potentially deploy to eastern Europe amid fears of a Russian invasion of Ukraine.

"We take our commitment to our eastern flank partners, NATO allies, very seriously," Psaki said, calling the U.S. commitment to NATO "ironclad." "The aggressive behavior here is on the part of the Russians. This is a defensive alliance, not an offensive alliance, and what we're doing here is not making a decision ... to deploy but just to be ready."

Psaki said that the U.S. forces are based in Europe and the U.S. and that the decision to place them on alert was a result of "collaborative" discussions with NATO partners.

Kremlin spokesman Dmitry Peskov reportedly accused the U.S. and NATO of escalating tensions on Monday with the preparations for potential troop deployments.

Russia has amassed over 100,000 troops at Ukraine's border and sent troops to Belarus to conduct military drills, raising concerns about the prospect of an invasion of Ukraine.

Biden admin briefing lawmakers

Psaki also confirmed that the Defense and State Departments are briefing bipartisan House and Senate leadership and committee staff on Russia and Ukraine in two classified briefings on Tuesday.

"We're also working on all members briefings for the House and the Senate in the coming days," she said, adding that the administration would continue to provide regular briefings as the situation unfolds.

Biden has received regular updates from his national security team about the situation and met with European leaders on a secure video call on Monday.

Psaki indicated that Biden would host an event with CEOs on his Build Back Better proposal at the White House on Wednesday in response to a question about Biden's schedule.

Psaki addresses Biden's harsh words

Psaki confirmed that Biden phoned Fox News correspondent Peter Doocy after being caught on a hot mic referring to the reporter as a "stupid son of a bitch" during an event at the White House on Monday afternoon.

"The president called him, he conveyed to him that 'it was nothing personal, man,' and also acknowledged that all of you are going to ask him a range of questions," Psaki told reporters when asked about the episode.

Psaki said she would not normally confirm private phone calls with the president, but noted that Doocy, who was in the White House briefing room Tuesday, detailed the conversation on his own the night prior.

"Can confirm, person familiar," Doocy quipped.

Doocy told Fox News host Sean Hannity on Monday evening that Biden called him on his cellphone and that the two talked about "just kind of moving forward."