Public safety exercises were underway today around Boston as about 2,000 police officers, firefighters, EMTs, and hospital staff staged training runs on various large-scale emergency scenarios.

As the 24-hour training dubbed “Urban Shield’’ unfolded, people used social media to share scenes from the exercises.

#urbanshield swat team hot rescue scenario at mit pic.twitter.com/fM4yELraws — Bruce Gellerman (@AudioBruce) May 3, 2014

All geared up for a day of #urbanshield SWAT training at the Lincoln School #usbos14 pic.twitter.com/t4m1GDyMJn — Brookline PD CSD (@CSD_INTERN) May 3, 2014