NATO is concerned that Russia may consider deploying nuclear weapons in outer space to target satellites. Secretary-General Mark Rutte warned of the possibility in an interview with the German newspaper Welt am Sontag.
Rutte said that Moscow's space capabilities are outdated compared to those of the West.
"So the development of nuclear weapons in space is a way for Russia to improve its capabilities. This is very worrying," Rutte said.
Although such weapons would not hit the Earth, shooting down satellites could have serious consequences as many systems used by NATO rely on satellites, including those for navigation, communications and environmental monitoring.
Rutte added that such a move by Russia would violate the 1967 Outer Space Treaty, signed by the United States and the Soviet Union. The treaty still provides a framework for international space law and prohibits the placement of weapons of mass destruction in space.
According to Rutte, NATO allies are adapting to new challenges, sharing information and developing more protected satellites.
"In recent years, space has become very populated. It has become dangerous and unpredictable. We know that the competition for space is fierce and is becoming more bitter, and not only in economic terms. It is something that affects our security," Rutte added.