Ukraine on Monday launched joint military exercises with the U.S. and a string of other NATO countries as tensions with Russia remain high over the Kremlin-backed insurgency in the country’s east.

The annual Rapid Trident military exercises, taking place in the western Ukrainian village of Starychi until September 15, involve some 2,200 soldiers from 14 countries.

“(The participants) stand in solidarity with Ukraine, for Ukrainian security, Ukrainian sovereignty, and Ukrainian territorial integrity,” the U.S. Ambassador to Ukraine, Marie Yovanovitch, said at the opening ceremony.

The drills start a week before Russia holds its biggest military exercises since the Cold War, with the participation of China and Mongolia. A spokesman for the Ukrainian drills, Taras Gren, said that some 350 pieces of military equipment will be used during the exercises.

The Ukrainian Border Guard Service and the National Guard troops will be involved for the first time, he said.