Authorities in Australia are investigating the origin of mysterious large silver spheres that washed up on a beach in northern Queensland this weekend.

The six solid objects discovered at Forrest Beach, north of Townsville, are believed to be space debris, and the Australian Space Agency (ASA) is now trying to determine where it came from. The BBC has contacted the agency for comment.

Crews in protective suits were reportedly seen placing the spheres into hazardous materials barrels under police guard, fearing they might contain dangerous substances.

The Queensland Fire Department said on Sunday that a 50-metre exclusion zone remained in place, and urged anyone who found a suspicious object in the area not to touch it.

He said members of the public who encounter them should leave immediately and call emergency services.

There has been some speculation online that the spheres are propellant tanks for spacecraft and could therefore contain residual amounts of a highly flammable or reactive substance.

But it is still unclear which vehicle or owner they came from.