April 13 (UPI) -- U.S. European Command Gen. Tod Wolters told lawmakers Tuesday that he is confident Ukraine could repel a new Russian invasion "over time."
At a Senate budget hearing, Wolters said his command remains "very, very vigilant" and concerned about Russia's rapid buildup near Ukraine in recent weeks, Stars and Stripes reported.
Ukrainian officials estimate that about 80,000 Russian troops are amassed on its border.
Wolters said the current Russian force "mirrors the size and scope and scale of the infiltration of forces that occurred back in 2014," when Russia annexed Ukraine's Crimean Peninsula.
Also Tuesday, President Joe Biden called Russian President Vladimir Putin to express concerns about the sudden buildup of Russian troops near Ukraine's border and called on Putin to de-escalate tensions, according to a readout of the call.
Defense Secretary Lloyd Austin announced plans Tuesday to send about 500 additional troops to Germany to improve the ability of the U.S. military to ramp up forces to defend allies, partially reversing a drawdown ordered by then-President Donald Trump last year.
Ukraine's foreign minister, Dmytro Kuleba, met with Stoltenberg Tuesday to discuss the country's current security situation.
"At the operational level, we need measures, which will deter Russia, and which will contain its aggressive intentions," Kuleba said at a joint press availability with Stoltenberg.
Both Stoltenberg and Kuleba suggested the alliance could impose new sanctions, which Kuleba said would "raise the price of Russian aggression."
"Russia must respect its international commitments," Stoltenberg said at the press availability with Kuleba. "NATO's support for Ukraine's sovereignty and territorial integrity is unwavering."