The fielding of an improved gravity bomb has been moved up to December as Vladimir Putin threatens the region.

Lloyd Austin told NATO allies in Brussels that the Nuclear Posture Review would maintain Washington’s decades-long nuclear declaratory policy of “calculated ambiguity." | Olivier Matthys/AP Photo

By Bryan Bender, Paul McLeary and Erin Banco

The United States has accelerated the fielding of a more accurate version of its mainstay nuclear bomb to NATO bases in Europe, according to a U.S. diplomatic cable and two people familiar with the issue.

The arrival of the upgraded B61-12 air-dropped gravity bomb, originally slated for next spring, is now planned for this December, U.S. officials told NATO allies during a closed-door meeting in Brussels this month, the cable reveals.