The attack, an apparent suicide bombing, is believed to be the worst terrorist strike on British soil since 2005, when London's public transport network was hit by a number of bombs which left 54 people dead.
Though this is the first terror attack to hit the city in years, Manchester is already a city marked by terrorism. The historically industrial, largely working-class city was the target of a number of bombings from the 1970s onwards. These attacks were orchestrated not by the Islamist extremists who claimed more modern attacks in Britain, but by the Provisional Irish Republican Army who sought to pressure the British government into accepting a united and independent Ireland.
The most famous of these attacks occurred almost 21 years ago, on the morning of June 15, 1996. The IRA detonated an enormous 3,300-pound truck bomb on Corporation Street in the commercial center of the city, not far from Monday night's attack at the Manchester Arena. It is still the largest bomb to explode in Britain since World War II.
In some ways, the response to the 1996 bombing wasn't so different than the 2017 attack. This Tuesday, the Arndale Centre shopping mall that bore the brunt of the Corporation Street bombing was evacuated again after fears that it might be targeted in a follow-up attack. Again, there are fears that an attack outside Britain's capital appears to have stretched the country's often London-focused intelligence community.
May also appears to have inadvertently mirrored the language of then-Prime Minister John Major, who called the attack a "callous act of terrorism" in a statement released in 1996. Major had dubbed the 1996 bombing the work of "a few fanatics" and said that the attack caused "absolute revulsion" in Ireland. Colin Phillips, a senior Manchester police officer who spoke to reporters after the attack, dubbed the IRA "absolutely evil criminals" for the plot - a statement which finds its own echo in President Donald Trump's criticism of the "evil losers" behind such attacks.
If Monday night's attack is proven to have links to Islamist extremists, there will be more parallels. Manchester is home to a large Muslim community. Mancunian Muslims may now find themselves expected to publicly express opposition to an act of terror or risk guilt by association, much like the city's sizable Irish population did in 1996. Accounts of the aftermath of the IRA bombing tell of how Irish nurses were told to go "home" by colleagues and Irish community centers received violent threats. A local politician soon set up an Irish festival to try and bridge the divides wrought by the attack.
Despite the similarities, the differences between the two attacks shows how the threat posed by terrorism has shifted in the past two decades. The attack at the Manchester Arena this week appears designed to inflict the maximum amount of deaths and injuries on a primarily young crowd, there to enjoy the music of American singer Ariana Grande. While the 1996 attack caused far greater damage to Manchester's buildings and saw more than 200 people wounded, no one died in the immediate aftermath of the attack.
This is in large part due to phone calls to local television stations and universities placed on the morning of June 15. Just an hour before the bomb went off, an Irish-accented man warned that there was a bomb in a van parked on the corner of Cannon and Corporation streets. The caller used a code word that let authorities know it was a real threat. Police sprang into action, evacuating around 80,000 people from the busy commercial hub of one of Europe's larger cities. By the time the bomb went off, only a handful of people were still in the area.
In fact, the IRA understood that any deaths caused by the blast could be end up being counterproductive to their cause. When they released a statement claiming responsibility for the attack June 20, the organization said it "sincerely regretted" the injuries caused to civilians.
Much remains to be discovered out about the perpetrator of this week's attack in Manchester. In particular, there will be a lot of interest in the ties between the suspect, who died in the attack, and the Islamic State. In the past, the extremist organization has claimed attacks for which it seemed to have no practical input other than inspiration. This loose relationship with potential attackers presents a confounding problem for intelligence agencies.
The men who planted the bomb in Manchester in 1996 have never been found, despite considerable leads at the time. The attack may well have led back to the IRA's leadership, but the drive to find the perpetrators ended up coinciding with a renewed push for peace in Northern Ireland. Less than two years after the attack, the Good Friday peace agreement was signed. The deal ultimately saw the IRA give up on using terrorist tactics in its struggle for a united Ireland, though there still remains dissension on the group's fringes.
Despite the damage wrought on the city in 1996, some now credit the attack with the rebirth of Manchester - a former manufacturing hub that had fallen into a slump after World War II and had become known as a gloomy, poor city. Development had long been planned in the city, but the huge amount of damage in Manchester's once-drab center presented a historic opportunity to wipe the slate clean and create a gleaming, steel and glass-filled commercial hub. The city is now well-known internationally for its sports teams, multiple universities and arts and culture.
But the city never forgot the attack. A red post box, one of the few objects left standing after the bomb, still sits on Corporation Street. It bears a gold plaque commemorating the blast from almost 21 years ago.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)