President Joe Biden called Ukrainian President Volodymyr Zelensky on Friday to pledge the United States’ “unwavering support for Ukraine’s sovereignty and territorial integrity in the face of Russia’s ongoing aggression in the Donbass and Crimea,” the White House announced.

Washington has cited Russian “aggression” amid the rising tensions in Ukraine as Russian troops and armor are rushing to the border region. Although Ukraine is not a member of NATO, President Biden has pledged American support of what he called “a strategic partnership” with Zelensky’s government “based on our shared democratic values that deliver justice, security, and prosperity to the people of Ukraine.”

Meanwhile, on Saturday, Ukraine’s military released a statement saying that its forces and NATO troops will hold joint military drills later this year. The planned military exercises, named Exercise Cossack Mace, will be conducted with over 1,000 troops from five different NATO countries.

In a thinly designed reference to the recent Russian troop build-up on Ukraine’s border, the exercise will include, “defensive actions […] followed by an offensive in order to restore the state border and territorial integrity of a state that has been subjected to aggression by one of the hostile neighboring countries.”