At the March 24th summit in Brussels, Biden will "reaffirm our iron-clad commitment to our NATO allies," Press Secretary Jen Psaki told reporters.

Biden will also attend an EU summit in Brussels to discuss the invasion of Ukraine and Western efforts to impose "economic costs on Russia, provide humanitarian support to those affected by the violence and address other challenges," Psaki said.

Psaki would not rule out Biden adding stops to his European trip, amid speculation that he could possibly meet with some of the three million refugees who have now fled Ukraine, according to the United Nations.

She said his "real focus right now is to meet with NATO partners in Brussels. If there are additional steps, we'll share all those details."

"We're still working through the final details," she said.