Fourteen PSNI officers were injured in a 12th consecutive night of violence in Northern Ireland.
Loyalists had cancelled a number of planned protests and had been urged to stay off the streets as a mark of respect following the death of Prince Philip.
However, police were pelted with petrol bombs and masonry during three hours of disorder yesterday evening.
The disorder took place in the Atlantic Road area of Coleraine, where a crowd of about 40 people, many of them wearing masks, attempted to block the road by setting fire to pallets.
Police were also attacked with missiles and a car was set on fire in a separate incident at Tiger's Bay, a loyalist area in north Belfast.
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Taoiseach Micheál Martin has warned against a "spiral back" into sectarian conflict in Northern Ireland.
In a statement marking the 23rd anniversary of the Good Friday Agreement, he said: "We owe it to the agreement generation and indeed future generations not to spiral back to that dark place of sectarian murders and political discord.
"There is now a particular onus on those of us who currently hold the responsibility of political leadership to step forward and play our part and ensure that this cannot happen."
Speaking in Cork today, Mr Martin called for reflection on the values of the Good Friday Agreement to inform the present.
Mr Martin said the agreement was founded on tolerance and parity of esteem between different traditions, as well as being about creating peace and reconciliation.
He said the leaders who negotiated the Good Friday Agreement were brave enough to move beyond where they had been to create a situation where younger generations had been spared "the terrible trauma of violence".
"I think it's extremely important that we remember that and that we reflect on that so as to inform the present and the current situation," Mr Martin said.
Mr Martin said he had spoken to "almost all" the political leaders in the North yesterday and there was common ground among them in terms of re-asserting the primacy of peace and the rule of law and democracy. He said all were agreed on the need to defuse tensions.
Today, two men charged with rioting offences in the Lanark Way area of west Belfast during the week were denied bail at Laganside Court.
North Area commander, Chief Superintendent Davy Beck, said: "The senseless disorder we saw unfold in a residential area in Coleraine has achieved nothing but leave people petrified in their homes.
"Such reckless criminal activity has only served to harm the local community by those who deliberately chose to engage in such disorder."
Disorder in Belfast last night (Friday 9 April) left 14 officers injured.
— Police Service NI (@PoliceServiceNI) April 10, 2021
Read our update and statement here:https://t.co/Dl2xjc9O7L
The disorder in Coleraine started at about 7.45pm, when police officers had two petrol bombs thrown at them.
Five more petrol bombs were thrown when more resources were deployed into the area.
Masonry and other missiles were also thrown at officers, causing damage to some police vehicles.
At about 10.45pm, officers had dispersed the crowd and restored order.
Mr Beck added: "Thankfully, none of our officers were injured as a result of the attacks, however some of our vehicles did sustain damage, and that damage is currently being assessed.
"I want to make a direct appeal to parents, guardians and community leaders to use their influence to ensure we do not see a repeat of such ugly scenes.
"This is not wanted by anyone and does not represent the local community who we know just want to live in peace.
"I want to reassure the community that we will continue to work to keep people safe and those who engaged in last night's disorder should be warned that an investigation is under way and evidence gathered will now be reviewed and those identified will face the full rigour of the law."
Leaders in Northern Ireland are fearful the chaos that has plagued the region in recent days will continue into the weekend.
Loyalists have urged their communities to end any protests as a mark of respect for the Duke of Edinburgh, who died on Friday.
Despite this, small pockets of unrest continued in parts of the province.
Police were attacked when they attended the scene of disturbance in Tiger Bay, with riot vans and police dogs in tow.
Some officers came under attack, with missiles such as stones, bottles and petrol bombs thrown at them.
There was a heavy police presence in the area overnight, with missiles also thrown at officers in the nearby, nationalist area of New Lodge.
Local SDLP MLA Cara Hunter said: "The last thing people in this community want is further disruption. I understand that tensions are running high but resorting to this kind of behaviour only damages local people and services.
"The crowd burning refuse, blocking roads and intimidating people in this community needs to stop. They need to go home and let people get on with their lives.
"This is a time for calm. Things don't need to escalate. Young people don't need to end up with criminal convictions. I'm appealing for everyone to exercise their influence to reduce tensions in our community."
Loyalist leaders had urged the community not to take part in protests on Friday after the death of the Duke of Edinburgh.
Signs posted in Lanark Way, the scene of much of the unrest of recent days, read: "We would ask all PUL (Protestant, Unionist, Loyalist) protests are postponed as a mark of respect to the Queen and the royal family.
"The continued opposition to the NI protocol and all other injustices against the PUL community will take place again after the period of mourning."
