The move came after Russian President Vladimir Putin on Monday ordered a halt to an agreement with the US on weapons-grade plutonium disposal in retaliation for Washington's "unfriendly actions."
Tensions have surged between the two powers after Washington suspended talks on a ceasefire in Syria over Moscow's continuing bombing campaign in support of President Bashar al-Assad's regime.
On Wednesday, the Russian government published orders signed by Prime
Minister Dmitry Medvedev and dated Tuesday calling for the "suspension" of a
2013 agreement on cooperation in scientific research and development in the nuclear and energy spheres.
Russia said this was a response to the US regularly extending sanctions over Ukraine, including by restricting cooperation on nuclear energy.
It said that in the current situation it was inadvisable to "allow American citizens into Russian nuclear installations" as well as to permit direct cooperation between Russian and US research institutions.
The suspension included an agreement between Russia 's nuclear agency Rosatom and the US Department of Energy to study converting Russian research reactors to use low-enriched uranium, Moscow said.
In reality, cooperation "has been dormant for two years," a spokesman for Russia 's nuclear agency Rosatom told TASS state news agency, with no new contracts planned.