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.

Beaches in the Australian city of Sydney have reopened for swimmers after being closed earlier this week when thousands of mysterious black tar-like balls washed ashore, prompting health concerns. Officials say tests found the balls to be formed from chemicals similar to those in cosmetics and cleaning products but it is still unclear where they came from.

MELBOURNE, Australia -- Australian authorities responded on Saturday to a reported bomb scare on flight from New Zealand to Sydney. Police said there was no threat. Air New Zealand flight 247 remained on the Sydney Airport tarmac with its passengers aboard for hours due to a bomb threat, news media reported.

There are reports of a bomb scare involving an incoming international flight at Sydney Airport. According to Seven News, the incident involves Air New Zealand flight NZ247 from Wellington to Sydney.