A mysterious Russian satellite displaying "very abnormal behaviour" has raised alarm in the U.S. government, according to a report by the BBC.

A U.S. State Department official speaking in Switzerland voiced fears to say it was impossible to rule it out as a satellite that had been weaponised. "We don't know for certain what it is and there is no way to verify it," said assistant secretary Yleem Poblete at a conference in Switzerland on 14 August.

The satellite in question was launched by Russia in October last year. "[The satellite's] behaviour on-orbit was inconsistent with anything seen before from on-orbit inspection or space situational awareness capabilities, including other Russian inspection satellite activities," Poblete told the conference on disarmament in Switzerland.

Poblete said that the U.S. had "serious concerns" that Russia was developing anti-satellite weapons.

The BBC reports that Russia has dismissed the comments as "unfounded, slanderous accusations based on suspicions".

Russia also said that it has repeatedly asked the U.S. to join a space treaty between Moscow and Beijing that prevents an arms race in space.

The comments made by the U.S. State Department representative come just days after U.S. Vice President Mike Pence announced his government’s decision to launch a sixth branch of the U.S. military called the ‘space force’. This branch was to be developed to counteract threats from Russia and China in space.

U.S. Defence secretary Jim Mattis speaking in Brazil said a space force is necessary to protect American satellites. He also said the U.S. has no plans to put weapons in space but emphasised the vital and growing role that satellites play not just in military operations but in the world economy.

He gave the example of China's use of a ground-based missile to destroy one of its own non-functional weather satellites in January 2007, and suggested it was a calculated demonstration to the United States of Chinese capabilities.

Mattis said, "We understand the message that China was sending - that they could take out a satellite in space. Since then our intelligence services have watched other nations, including Russia, develop a space attack capability."

He added that the U.S. cannot ignore potential threats to satellites that are crucial to communication, navigation, weather information and other underpinnings of modern life.

The U.S. military has worked on anti-satellite weaponry in the past but has no deployed weapon dedicated to that mission today.

(The above story first appeared on LatestLY on Aug 16, 2018 06:59 AM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).