President Obama’s call Wednesday to reduce U.S. and Russian nuclear stockpiles by one-third ran into immediate opposition in both Washington and Moscow, with officials from both countries questioning the need for such a sharp cut in their weapons arsenals.

Obama’s proposal, which he made during a speech at Berlin’s Bradenburg Gate, would reduce U.S. and Russian stockpiles of nuclear weapons to roughly 1,000 each, down from the 1,500 outlined in the current treaty between the superpowers.