Russia on May 21 said the United States was seeking to place weapons in space, the latest accusation in an ongoing row that comes a day after Washington vetoed a Russian non-proliferation motion at the United Nations.
"They have once again demonstrated that their true priorities in the area of outer space are aimed not at keeping space free from weapons of any kind, but at placing weapons in space and turning it into an arena for military confrontation," Russia's Foreign Ministry spokeswoman Maria Zakharova said in a statement.
The two superpowers have traded multiple accusations of seeking to weaponise space in recent months.
In February, Washington said it was concerned by an "anti-satellite capability that Russia has developed" after U.S. media outlets reported that intelligence agencies had warned their allies that Russia could launch a nuclear weapon into orbit.
Moscow denied those accusations as "malicious" and "unfounded," saying it does not possess such systems.
Russia has since levelled similar charges at the United States.
Kremlin spokesman Dmitry Peskov did not provide further details on Tuesday when asked if Moscow had specific information regarding U.S. plans to deploy weapons in space, saying only that the country's intelligence agencies were monitoring the situation.
"Our special services are performing their work," he told reporters in a briefing.
The countries have proposed rival non-proliferation motions at the United Nations as part of the spat.
Russia vetoed the U.S. initiative last month, while Moscow's proposal was blocked by the United States, Britain and France in a vote on Monday.
Moscow said the U.S. initiative focused only on nuclear weapons and that Washington was not seriously interested in a complete ban on weapons in space.
The veto by the United States and its allies "spoke eloquently" about their priorities, Mr. Peskov said Tuesday.
U.S. envoy Robert Wood said Russia's proposal, which called on all countries to "take urgent measures to prevent for all time the placement of weapons in outer space," was a distraction and accused Moscow of "diplomatic gaslighting."
Ms. Zakharova said Tuesday that Russia "will continue to make an unwavering contribution to keeping outer space free of weapons of any kind and preventing it from becoming another sphere of tension and armed confrontation."
Space is a rare area where the two countries still have a degree of cooperation despite a swathe of Western sanctions and dire relations amid Russia's offensive on Ukraine.
Both countries ferry each other's crew members to and from the International Space Station (ISS), where their astronauts are jointly stationed.