A police operation was underway at the Sydney Opera House on Thursday (January 14) , police said, with at least one ferry leaving the area cancelled and media reporting that people were being cleared away from the site.

A police spokeswoman said an operation was going on but could not provide any details.

“Basically, we were doing a bit of steel work in the basement of the Opera House about 20 minutes ago and about 30 to 40 coppa’s stormed through the place and asked everyone to evacuate, take all their gear and leave straight away,” said construction worker, Tristian Callister who was evacuated from the building.

The Twitter account of the city’s ferry service said one ferry service had been cancelled due to the operation.

Australia is on heightened alert for attacks by home-grown militants. Authorities say they have thwarted a number of potential attacks, although there have been several “lone wolf” assaults.

Police said later after the operation ended that another operation had been carried out in Manly, a beach suburb 15km north of the city’s central business district and that had also concluded about an hour later. They said the operations were carried out as a precautionary measure. (Reuters)