A gunshot was fired at police during serious disorder linked to a security alert in Co Armagh.
Officers came under sustained attack for a number of hours last night, with more than 100 petrol bombs thrown at their cordons in the area of the alert.
The area in Lurgan has been targeted many times before by dissident republicans.
Up to 25 paint bombs, bricks and other masonry were also hurled by a large and aggressive crowd which gathered at around 9pm and remained until the early hours of the morning at Lake Street.
No officers or members of the public were injured, however police vehicles were damaged.
Police Service of Northern Ireland superintendent David Moore said: "The behaviour of those involved in the disorder last night was nothing short of disgusting.
"At one point, a gunman emerged from this crowd and fired at least one shot at police. Mercifully no one was hurt.
"Local police officers and tactical support group colleagues were on the receiving end of orchestrated, intense and prolonged violence for a number of hours last night, all while trying to keep this community safe from what is potentially an explosive device close the railway line."
Two devices found close to the Portadown railway line were discovered to be hoaxes.
The line was closed and bus transfers were in operation between Newry and Belfast for Dublin/Belfast rail service, however it has since been re-opened.