Authorities have shut down two beaches in Sydney, Australia, on Wednesday after hundreds of black golf ball sized spheres washed ashore.

A local mayor says the balls littering two beaches in the Sydney area could be "tar balls," which form when spilled oil clumps together with debris in the water.

Hundreds of mysterious black tar-like balls have washed up on two popular Sydney beaches, prompting lifeguards to close the strands to swimmers.

Two popular eastern Sydney beaches were closed until further notice after the appearance of "mysterious black" balls, local authorities said. Coogee beach, particularly popular with backpackers, was cleared on Tuesday after lifeguards "discovered mysterious,

Lifeguards evacuated 'Coogee Beach' in the eastern Australian coastal city of Sydney after finding mysterious, black balls along the entire length of the beach. The beach was already closed until further notice as it is not immediately clear what exactly is going on.

Both beaches were closed following the discovery of the balls and remain closed amid ongoing cleanup efforts. Randwick Council staff are being assisted by working with the NSW Env