"Russia has launched a satellite into low-Earth orbit that we assess to be a space weapon, capable of attacking other satellites," Pentagon spokesman Brigadier General Pat Ryder told reporters at a news conference.

The alleged Russian space weapon, launched on May 16, was placed "in the same orbit as a U.S. government satellite," he said.

Ryder said that Washington was prepared to defend its interests and would continue to monitor the situation.

"We have a responsibility to be prepared to protect and defend the domain, the space domain," he said.

Kremlin spokesman Dmitry Peskov declined to comment on reports that Moscow had launched a space weapon.

"I cannot comment on this topic. We are acting in full compliance with international law, we are not violating anything and we have repeatedly advocated for the prohibition of any weapons in space," Peskov told a news conference.

"Unfortunately, our initiatives have been rejected, including by the United States," he said.

On Tuesday, Moscow also accused the United States of seeking to put weapons in space, after the UN Security Council on Monday rejected a Russian draft resolution on preventing an arms race in space.

"They have demonstrated once again that their real priorities in outer space are not to keep space free of any weapons, but to put weapons in space and turn it into an arena of military confrontation," Russian Foreign Ministry spokeswoman Maria Zakharova said in a statement.

In recent months, the two superpowers have traded accusations of seeking to weaponize space.

Against that backdrop, both Washington and Moscow have put forward non-proliferation resolutions at the UN Security Council.

Russia vetoed the U.S.-led effort last month, while Moscow's proposal was defeated on Monday after failing to secure the nine votes needed for adoption. (Seven countries voted against, including the United States, Britain and France.)

U.S. Deputy Ambassador to the United Nations Robert Wood said Russia's proposal, which called on all countries to "take urgent measures to prevent the placement of weapons in outer space," was a "distraction" and accused Moscow of "diplomatic manipulation."

He said Moscow's May 16 launch followed "other Russian satellite launches likely intended to test anti-satellite weapons systems in low-Earth orbit in 2019 and 2022."

In February, the White House said Russia was developing an anti-satellite weapon.

Tensions between Moscow and Washington over the war in Ukraine have revived Cold War-era fears of the militarization of space, despite a 1967 treaty that calls for "the non-emplacement of nuclear weapons or any other kinds of weapons of mass destruction in orbit."

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