File photo: CFP

Russia will station tactical nuclear weapons in neighboring Belarus, President Vladimir Putin said on Saturday, marking the first time since the mid-1990s that Moscow will have based such arms outside the country.

"Tactical" nuclear weapons refer to those used for specific gains on the battlefield rather than those that can wipe out cities. It is unclear how many such weapons Russia has given that it is an area still shrouded under nuclear nonproliferation agreements.

Putin told state television that Belarusian President Alexander Lukashenko had long raised the issue of stationing tactical nuclear weapons in his country.

"There is nothing unusual here either. Firstly, the United States has been doing this for decades. They have long deployed their tactical nuclear weapons on the territory of their allied countries," he said.

"We agreed that we will do the same without violating our obligations – I emphasize, without violating our international obligations on the nonproliferation of nuclear weapons."

According to Russia's state media report, Moscow would not transfer nuclear arms control to Minsk.

The United States reacted cautiously. A senior U.S. administration official noted that Moscow and Minsk had been speaking about the transfer of nuclear weapons for some time.

"We have not seen any reason to adjust our own strategic nuclear posture nor any indications Russia is preparing to use a nuclear weapon. We remain committed to the collective defense of the NATO alliance," the official said.

Putin did not specify when the weapons would be transferred to Belarus, which has borders with three NATO members – Poland, Lithuania and Latvia.