A U.S. defense official says the Obama administration is pursing ways to counter Russia's violation of a key arms control treaty, but says actions will be rolled into a broader response to Kremlin aggression in Ukraine and other parts of the world.

The U.S. announced last year that Russia is violating the Intermediate-Range Nuclear Forces Treaty signed in 1987.

Russia has not acknowledged violating the treaty, which says the U.S. and Russia cannot possess, produce or test-fly a ground-launched cruise missile with a range of 300 to 3,400 miles.

Republican lawmakers have been calling on the administration for more than a year to hold Russia accountable.

Deputy undersecretary of defense Brian McKeon on Tuesday broadly outlined the U.S. response, and promised lawmakers more details in a classified setting.