If Russian leader Vladimir Putin is to be believed, at some point during the summer Russia moved some of its short-range nuclear weapons into Belarus, closer to Ukraine and at the doorstep of NATO’s members in Central and Eastern Europe.

Putin’s declared deployment of the weapons onto the territory of its neighbor and loyal ally marks a new phase in the Kremlin’s nuclear saber-rattling over its invasion of Ukraine.

Neither Putin nor his Belarusian counterpart, Alexander Lukashenko, divulged how many were moved, only saying that Soviet-era nuclear arms depots in the country had been readied to accommodate the weapons, noting Belarusian pilots and missile crews have been trained to use them.

The United States and NATO haven’t confirmed the move and doubts remain.