In Austria:
"Many women and girls have also been attacked. Some told me they were attacked on the Staatsbrucke, some in the marketplace and others at the train station."
"They tried to beat them off, but they were overcome and one of them was grabbed by the head. He was cuddling her and licking her face."
"In another case a 28-year-old, also from Afghanistan, shortly after midnight had attacked a woman from Salzburg after grabbing her from her scooter."
"And in Switzerland, six women reported identical crimes in Zurich on New Year's Eve, while Finnish police intercepted information suggesting similar attacks were planned."
So if all of this is accurate (pinch of salt due to DF source) this was indeed a terrorist attack.