https://www.bbc.co.uk/news/live/world-u ... a-62042058
* What do we know about the rooftop position?
* 'Enough is enough', - congressman at parade
* Shooter 'discreet' with a 'high-powered rifle' - police
* 'We're hiding in a shelter now'
A hospital spokesperson tells the Reuters news agency there are 31 injured, mainly for gunshot wounds, but also some who were injured in the crush as people fled the scene of the Fourth of July parade.