Several NBC 5 viewers called our newsroom for answers about some very loud sirens in Arlington Friday night.
Police tell us they are also receiving calls and say the sirens are not tornado warning sirens.
City leaders say the sounds came from the Trinity River Authority on Northeast Green Oaks Boulevard.
Reports from Twitter said the sirens had been going on and off for hours.
The cause for the sirens was not immediately known, but the city says the sounds were not related to the outdoor warning sirens.