Fireworks were deliberately aimed at police during a night of Bonfire Night disturbances in two Leeds suburbs.
Officers in riot gear were sent to both Hyde Park and Harehills on Sunday night to deal with separate incidents of disorder.
Groups of youths blocked streets with bins before setting them alight and throwing lit fireworks at both police and firefighters sent to the scene.
In the Harehills incident, a large group barricaded Harehills Road, close to Banstead Park and St Aidan's Church, with bins and other items just after 9pm.
The bins were set on fire and fireworks were thrown.
Officers in protective equipment, including helmet and shields, were deployed to the area and dispersed the group. Firefighters put out the fire and the road was cleared a short time later.
No-one was injured and no properties were damaged. Two police vehicles were damaged during the incident and a number of residents reported low-level damage to their vehicles.
Queens Road in Hyde Park was also blocked with bins just before 10pm, and officers dispersed the group with no reports of injuries.
Detective Superintendent Lisa Atkinson said:
"While the bonfire weekend often brings an increase in incidents of firework-related anti-social behaviour, these two incidents were more serious and required officers to deploy in full protective equipment to deal with them.
"Both incidents were dealt with quickly and the groups dispersed but we don't underestimate the impact this behaviour will have had on people living in those areas.
"It is completely unacceptable and we are currently carrying out criminal investigations into both incidents to identify those involved and take appropriate action against them.
"We are making detailed enquiries into both incidents, including checking CCTV footage, and we would like to hear from anyone who has any information that could assist our investigations.
"Officers from the local neighbourhood policing teams are aware of the incidents and will be continuing to patrol the areas to reassure residents."
Anyone with information is asked to contact Leeds District CID quoting crime number 13170516886 or call the independent charity Crimestoppers anonymously on 0800 555 111.