Paris (AFP) - The city of Londonderry, where a woman was shot dead in rioting late Thursday, has been a flashpoint in three decades of sectarian unrest in Northern Ireland that left 3,500 people dead until a peace deal was reached on Good Friday 1998.
Called The Troubles, the violence pitted Protestants who were loyal to British rule against Catholics who wanted to unite with neighbouring Ireland, the Irish Republican Army (IRA) guerrilla group emerging to back this cause.
Police said republican dissidents "most likely" from a group called the New IRA were behind Thursday's violence in the city in which vehicles were set ablaze, petrol bombs thrown and shots fired at police, resulting in the death of the 29-year-old journalist.
Here is some background about Londonderry (also known as Derry) and Northern Ireland's sectarian conflict.
- Londonderry spark -
Clashes erupted when police used force to break up a peaceful Catholic civil rights demonstration in Londonderry, the British province's only Catholic-majority city, in 1968.
It inflamed tensions between Catholics and Protestants, sparking violence in Londonderry and Belfast.
In 1969 Britain deployed troops to face the unrest. The following year the Provisional Irish Republican Army (IRA) undertook a campaign of bombings and shootings against the troops.
The IRA violence was reciprocated by unionist paramilitary groups, driving a wedge between the communities.
- Bloody Sunday -
In one of the worst incidents in The Troubles, British troops opened fire on a Catholic civil rights march in Londonderry on January 30, 1972, leaving 14 people dead.
The Sunday march was illegal and police and British paratroopers had received orders to begin arresting marchers.
At around 4:10 pm, the troops opened fire. They claimed afterwards to have acted after coming under sustained attack by gunfire and nailbombs, and to have aimed away from the demonstrators.
This version was challenged in a 2010 report published after a 12-year investigation that said British troops fired first and their victims were unarmed.
Following the report, then British prime minister David Cameron apologised for the killings, saying the shooting was "both unjustified and unjustifiable."
An ex-paratrooper was in March 2018 charged for two of the deaths.
"Bloody Sunday" was a turning point in the IRA campaign. Its ranks swelled and it extended its bombing campaign to the British mainland with deadly attacks on pubs in 1974 and the assassination of Lord Louis Mountbatten in 1979.
- Good Friday breakthrough -
Peace efforts stalled until in July 1997 the IRA declared a new ceasefire after its political wing, Sinn Fein, was offered a place at the negotiating table.
It lead to lengthy negotiations that culminated in an agreement reached on Good Friday, April 10, 1998, between London, Ireland and the main Northern Ireland political parties, backed by the IRA.
The Good Friday Agreement led to a new semi-autonomous Northern Ireland with a power-sharing government between Protestants and Catholics.
The IRA declared a formal end to its armed campaign in 2005, saying it would pursue its aims through peaceful means, and Sinn Fein became part of the Northern Irish executive.
However dissident offshoots on both sides of the divide remained violently opposed to the peace accord, continuing sporadic unrest and bomb threats.
In one such incident, the new IRA was blamed for a car bomb outside courthouse in Londonderry on January 19 that caused no injuries but alarmed the violence-weary city. Four men were arrested.