Russia in October 2017 launched a satellite which has been observed behaving in an

The United States has challenged Russia about a satellite orbiting the earth exhibiting "abnormal behaviour", raising questions about Moscow's intentions to develop space weapons.

A US official said the satellite was acting suspiciously, describing its recent launch as “a very troubling development” that appears to justify Donald Trump’s plans for a new Space Force branch of the armed forces.

“Its behaviour on-orbit was inconsistent with anything seen before,” Yleem Poblete, the assistant secretary at the state department’s bureau of arms control, verification and compliance, told a UN disarmament conference in Geneva on Tuesday.

“We are concerned with what appears to be very abnormal behaviour.”

Russia dismissed her comments as "unfounded, slanderous accusations based on suspicions".

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Dr Poblete said that the satellite, launched in October 2017, was of particular concern given Russia’s repeated public statements about wishing to develop space weapons.

On March 1 Vladimir Putin, the Russian president, announced that his country’s Space Troops have received a mobile laser system, and Dr Poblete noted that Mr Putin has himself alluded to space weapons being more “acceptable in the political and military respect.”

She said Russia’s proposals for a treaty described by Sergey Lavrov, the foreign minister, as securing the “prevention of an arms race in outer space”, were not to be taken seriously.

Vladimir Putin, the Russian president, pictured in July Credit: TASS

However, Russia, with the support of China, has drafted what is known as the PPWT – a “Treaty on the Prevention of the Placement of Weapons in Outer Space, the Threat or Use of Force against Outer Space Objects”.

Dr Poblete raised concerns about the treaty at the Geneva convention on Tuesday, describing it as “a flawed document, proposed by a country that has routinely violated its international commitments”.

She used questions about the satellite to illustrate US unease about signing up to the draft treaty.

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Referring to the satellite, she said: “For the United States, this information strengthens our belief that the proposed PPWT has major flaws that make it unviable and demonstrates that any space arms control agreement is unverifiable at this time.”

A Long March-4C rocket lifts off from the southwestern Xichang launch centre carrying the Queqiao ("Magpie Bridge") satellite in Xichang, China's southwestern Sichuan province on May 21, 2018 Credit: AFP

Instead, she urged countries to follow America’s lead and dismiss the proposed treaty.

Alexander Deyneko, a Russian delegate at the Swiss conference, called Dr Poblete’s remarks “the same unfounded, slanderous accusations based on suspicions, on suppositions and so on”.

The United States had not proposed amendments to the draft treaty, Mr Deyneko said.

“We are seeing that the American side are raising their serious concerns about Russia, so you would think they ought to be the first to support the Russian initiative,” he said.

The row about the mystery satellite came after Mr Trump last week unveiled his his much-vaunted Space Force, a new 'sixth branch' of the armed forces which he wants ready by 2020.

China, which is backing the Russian treaty, has also been proactive in the development of space capabilities, since President Xi Jinping said in June 2013, at the launch of the Shenzhou X manned mission, that China would take bigger steps in space exploration in pursuit of its “space dream”.

A report for the US and China Economic and Security Review Commission highlighted how the Chinese military was seeking to develop the ability to attack US systems in space.

A Soyuz 2.1b rocket booster with a Frigate upper stage block, the Meteor-M 2-1 meteorological satellite and 18 small satellites launched from the Vostochny Cosmodrome Credit: TASS

The report stated: “Chinese analysts surmise that the loss of critical sensor and communications capabilities could imperil the US military’s ability to achieve victory”.

Chinese anti-satellite capabilities are thought to include spacecraft armed with weapons such as explosive charges, lasers and radio frequency jammers.

Additionally, trials of the Dong Neng-2 rocket from the Xichang launch site, a so-called missile defence interceptor, reached altitudes of over 18,000 miles; the range thought to include many US spy satellites in geosynchronous orbit, that make one orbit of the earth every day.

The Space Force will be used in conjunction with the new Space Fence – a ground-based radar, designed by US defence company Lockheed Martin, which will chart space debris as small as 1cm in diameter in the earth’s atmosphere.

Nasa, the US space agency, estimates there are over 500,000 individual pieces of space debris orbiting the planet at speeds in excess of 17,000 miles per hour. Satellites and manned spacecraft such as the International Space Station are at risk from such fast-moving space debris.

The Space Fence could be used alongside RAF Fylingdales as part of a system to track Russian and Chinese satellites. It monitors all space debris and traffic, including foreign owned space systems.

Whilst technically possible, the ability to physically interfere with satellites - known as a hard-kill - such as forcing them to descend into the earth’s atmosphere where they will burn up, is some years away. More likely is a cyberattack - known as soft-kill - that could render them useless or unable to communicate properly.

"The UK does not have the industrial muscle or money to do a hard-kill,” an RAF spokesman said, “but the US probably will in the near future and the UK will look to get involved.”

“We do have some soft-kill capability, such as jamming," he said.