BERLIN - US President Barack Obama will announce on Tuesday he will pursue a new reduction in deployed nuclear weapons, aiming to cut them by up to one third below the level achieved in the last "New START" treaty with Russia, a senior administration official said.

"The President will also articulate the goal of reducing US and Russian tactical nuclear weapons in Europe, pledging to work with NATO allies to develop proposals that can be explored with Russia to achieve this goal," the official said.