Over 40 police officers have been injured in violent incidents, with petrol bombs thrown, cars set alight and a bus hijacked in Belfast last night (April 7) before being set on fire.
The violence has been fuelled by loyalist frustrations over a failure to prosecute attendees - including a number of Sinn Féin politicians - at a public funeral for republican Bobby Storey which broke Covid regulations.
Concerns about the NI Protocol in the Brexit deal have also fuelled the unrest.
Who are loyalists, unionists, nationalists and republicans?
In very basic terms, unionists and loyalists believe Northern Ireland should remain a part of the UK and are usually Protestants.
Nationalists or republicans believe, on the other hand, that Northern Ireland should become part of a united Ireland. They are mainly Catholic.
The terms “unionist” and “loyalist” are often used interchangeably. However, there are some differences in their usage, with the term “unionist” referring largely to the political position that Northern Ireland should remain a part of the United Kingdom.
Political parties, such as the Democratic Unionist Party, (DUP) refer to themselves as unionists.
Since the Troubles began, “loyalist” tends to be used in reference to unionists who hold a stauncher position on the United Kingdom, sometimes advocating more extreme methods, such as violence, to remain in the union.
Paramilitary groups, such as the Ulster Volunteer Force (UVF), are considered loyalists.
Similarly, the terms “nationalist” and “republican” are sometimes used interchangeably, though there are again some subtle differences between the two.
Some historians and commentators would argue that nationalists are people who seek irish reunification through peaceful methods like political negotiation, while the term “republican” is sometimes used to describe people who would seek more radical means for reunification.
The Troubles, sometimes known as the Northern Ireland conflict, took place between 1968 and 1998 was an armed and violent conflict between nationalists / loyalists who wished Northern Ireland to remain a part of the UK, while nationalists / republicans wanted the province to unify with the Republic of Ireland.
Who are the DUP and Sinn Féin?
The Democratic Unionist Party (DUP) was founded by Ian Paisley in 1971 during the Troubles, and is a unionist political party.
Currently the party holds - by a slim margin - the most seats in the Northern Ireland Assembly, and is led by Arlene Foster, who is Northern Ireland’s first minister.
Sinn Féin, meanwhile, is a republican/nationalist party which was founded in 1905 by Arthur Griffith. It is a party which has been historically associated with the IRA, though some leaders would reject this link.
They form the second largest party in the Northern Ireland Assembly.
Why has there been violence in Northern Ireland?
Tensions have been rising in Northern Ireland for some time thanks to growing frustration and anger over trade deals separating the region from the rest of the UK.
The Northern Ireland Protocol, an element of the Brexit deal relating to Northern Ireland, has already caused some disruption at ports.
Loyalists and unionists were also angered after it emerged last week that Sinn Féin politicians who attended the funeral of republican Bobby Storey would not be prosecuted by the PSNI in spite of the event contravening current coronavirus rules.
In total, 24 Sinn Féin politicians attended, including Deputy First Minister Michelle O'Neill.
In the wake of the scandal, all major unionist parties called for the Police Service of Northern Ireland (PSNI) chief constable Simon Byrne to resign - saying communities have lost confidence in his authority.
In County Antrim, recent drug raids by the police against the South East Antrim Ulster Defence Association (UDA) have also further exacerbated tensions.