A hollow sphere that apparently crashed into Earth from space has left authorities scratching their heads.

The mystery ball left a 13ft wide crater and locals claimed to have heard several explosions before the discovery , near a village in the north of the African nation, 480 miles from the capital Windhoek.

Police forensics director Paul Ludik told the AFP news agency the sphere had a diameter of 14 inches, a rough surface and appears to be “two halves welded together”.

He added: “It is not an explosive device, but rather hollow.”

The discovery, made in November, but not made public until now, has prompted speculation over whether the mystery sphere is evidence of extra-terrestrial life.

Other sources claim it may be a hydrazine tank, which are usually used to store flammable liquid on space satellites, the Daily Mail said.

In the meantime, Nasa and the European Space Agency have been notified to carry out further tests on the object.

Similar spheres have reportedly been found in southern Africa, Australia and Latin America in the past two decades.