Trouble has flared for a fifth consecutive night in Londonderry.
The disorder again centred on the nationalist Bogside area of Derry.
The latest disturbances came a day after dissident republicans were blamed for firing at police with an automatic weapon in the area.
On Wednesday night youths armed with petrol bombs and stones threw missiles into the nearby unionist Fountain estate and at police stationed on the city's historic walls.
A fire was also started at the bottom of the flyover in the Bogside. Young people were seen stoking the burning wooden pallets, preventing cars from entering or exiting the roadway.
Earlier, police blamed dissident republican terrorists for firing a volley of automatic gunfire on officers.
Six shots were fired at officers close to the city's famous walls on Tuesday night.
None of the officers were injured and the bullets were found both in the walls themselves and nearby trees.
It is believed the shots were automatic gunfire which came from the vicinity of the Bogside Inn.
Around 16 petrol bombs and five paint bombs were also thrown close to the walls and at police patrols.
The Police Service of Northern Ireland (PSNI) are treating the incident as attempted murder.
District Commander Superintendent Gordon McCalmont said they believe dissident republicans fired the shots, and engineered the recent disorder.
"Officers who were in the city last night to deliver a community safety operation are wakening up this morning trying to come to terms with what could have been," he said earlier on Wednesday.
"We are offering them every support.
"It is quite clear that this attack was carried out by violent dissident republicans who we believe engineered the disorder we have seen in the city over the last number of nights.
"While this is a serious and disturbing escalation it will not deter us from doing our job and that is protecting the people of this district."
Northern Ireland Secretary Karen Bradley led condemnation of the incident.
"Anyone, who was in this part of the city, at this time, including children or young people could have been killed," she said.
"This murderous attack has to be condemned by all right-thinking individuals.
"I would call on all people of influence within the community to continue their efforts to encourage dialogue and reduce tensions.
"Anyone with any information about these incidents should contact the police.
"We will continue to work with the police to keep people safe."
Earlier, the leaders of all of the main political parties united to condemn attacks on the police amid ongoing unrest in Londonderry.
The DUP, Sinn Fein, Ulster Unionists, SDLP and Alliance issued a rare joint statement condemning the attacks and calling for an end to the violence.
They said: "There must be a strong, clear and united voice against those who would engage in such disgraceful violence.
"As a society we must all stand with those who maintain law and order and who protect all sides of our community.
"We condemn any illegal activity and urge those who are damaging their own community and intimidating their neighbours to stop."