美国提出削减核武新目标

US President Barack Obama is expected to propose that the US and Russia cut their strategic nuclear warheads by a third, in a major speech in Berlin on Wednesday.

Obama will also call for cuts in tactical nuclear arsenals in Europe. And he will commit to attending a nuclear security summit in the Hague next year, as well as holding a meeting on the issue in the final year of his presidency, in 2016.