Nashua police say they don’t know what caused several loud “booms” Saturday afternoon that were heard across Southern New Hampshire.

Many reports came from Nashua and surrounding towns, but the sounds were reported as far north as Manchester and as far south as Westford, Massachusetts.

Some who heard it in Nashua said they felt their houses shake.

Police and fire departments said they have not been alerted to any incidents related to the noise in the area.

The cause is still unclear.