Loud noises in Warsaw?

Just sitting in Jazdów park enjoying the autumn air, and out of nowhere at around 18:20 I hear loads of what sounded like bursts of gunfire in the distance, from the other side of the Vistula most likely as it didn’t sound close. I doubt it was fireworks as it was still light and it’s a Sunday. Then hundreds of birds all around roosting the trees suddenly all fly away, most likely they got scared, it was all rather terrifying. Then moments later I heard dozens and dozens of Police sirens and a few ambulance sirens coming from everywhere going in a similar direction, they were loads going for about 15mins, and you can still hear them in the distance, but still every few minutes you can hear a few heading in the same direction. Anyone know what it was? Did anyone else hear all the commotion?