Moscow on Thursday said US reports it was planning to launch a nuclear weapon into space were "malicious," "unfounded" and a White House ploy to try to pass a stalled Ukrainian aid package.

Citing unnamed official sources, US media reported Wednesday evening that Washington believed Russia was advancing plans to deploy a space-based nuclear weapon.

The potential goal was to use it to knock out Western satellites.

Senior Moscow officials on Thursday downplayed the reports.

They said it was a US attempt to denigrate Moscow and put pressure on Republicans in the House of Representative to back a multi-billion dollar aid package for Ukraine.

Kremlin Spokesman Dmitry Peskov said the White House was "trying to get Congress to vote on the appropriations bill any way it can", the state-run TASS news agency reported.

"It's obvious. Let's see what tricks, so to speak, the White House is going to pull," he was quoted as saying.

Deputy Foreign Minister Sergei Ryabkov, who is involved in Russia's nuclear policy, said the United States should provide evidence of its claims.

"It fits the trend over the last decade of the Americans engaging in malicious fantasising, attributing all sorts of actions or intentions to us that don't suit them," TASS cited Ryabkov as saying Thursday.

"We constantly say to them that unfounded accusations of various types are not something that we will respond to.

"If they make any kind of claim, they should accompany it with evidence," he added.

Washington and Moscow have repeatedly clashed verbally over nuclear policy since Russia launched its full-scale military campaign on Ukraine.

The West has accused Russia of reckless nuclear rhetoric after President Vladimir Putin said he was prepared to use a nuclear weapon if he felt an existential threat.

The Outer Space Treaty, of which both Russia and the United States are parties to, bans the deployment of nuclear weapons in space.