Question: The group that took responsibility for a mass shooting that happened in 1993 blamed it on an event carried out by who?
Context: The USA Pro Cycling Challenge, also known as USA Pro Challenge, was an annual multi-day professional road bicycle racing stage race that first took place in Colorado in 2011.  Originally announced on August 4, 2010 by Colorado Governor Bill Ritter and Lance Armstrong as the Quiznos Pro Challenge, the event carried on the state's cycling legacy, which was most notably highlighted by the Coors Classic that ran from 1980 to 1988.  On February 4, 2011 Richard E. Schaden, founder of Quiznos and the event's co-chairman, announced the investment of an initial $10 million to secure the initial growth and longevity of the race.  The USA Pro Cycling Challenge was one of only three current 2. HC rated races in the United States (along with the Tour of California, and the Tour of Utah), and was considered one of the most important pro cycling races in the U.S. The Shankill Road bombing was an operation carried out by the Provisional Irish Republican Army (IRA) on 23 October 1993 and is one of the most notorious incidents of the Troubles in Northern Ireland.  The IRA's intention was to assassinate the loyalist Ulster Defense Association leadership, who were to be meeting in a room above Frizzell's fish shop on Shankill Road, Belfast.  Two IRA members were to enter the shop disguised as deliverymen, then force the customers out at gunpoint and plant a time bomb with a short fuse.  However, when the IRA members entered the shop with the bomb, it exploded prematurely.  One of the IRA members was killed along with a UDA member and eight Protestant civilians.  More than fifty people were wounded.  Unbeknownst to the IRA, the meeting had been rescheduled. A mass shooting occurred during early morning on New Years Day on January 1, 1990 during a party in Narsaq of the municipality of Kujalleq in Greenland of the Kingdom of Denmark.  Seven people were killed and one was critically wounded in the worst mass shooting in the autonomous constituent country's history. On 5 February 1992, a mass shooting took place at the Sean Graham bookmaker's shop on the Lower Ormeau Road in Belfast, Northern Ireland.  Members of the Ulster Defence Association (UDA), a loyalist paramilitary group, opened fire on the customers, killing five civilians and wounding another nine.  The shop was in an Irish nationalist area, and all of the victims were local Catholic civilians.  The UDA claimed responsibility using the cover name "Ulster Freedom Fighters", and said the shooting was retaliation for the Teebane bombing, which had been carried out by the Provisional IRA less than three weeks before. A mass shooting is an incident involving multiple victims of firearms-related violence.  The United States' Congressional Research Service acknowledges that there is not a broadly accepted definition, and defines a "public mass shooting" as one in which four or more people selected indiscriminately, not including the perpetrator, are killed, echoing the FBI definition of the term "mass murder".  Another unofficial definition of a mass shooting is an event involving the shooting (not necessarily resulting in death) of four or more people with no cooling-off period.  Related terms include school shooting and massacre.  The lack of a single definition can lead to alarmism in the news media, with some reports conflating categories of crimes. A "crisis actor" is a term describing a hypothetical actor who participates in a false flag event such as a bombing or mass shooting simulated by the conspirators —usually government or corporate forces— in order to achieve some goal such as justifying increased government surveillance, disarmament of the population, or military action against blamed nations or groups.  Crisis actors are claimed in this context to play the part of bystanders or witnesses, emergency response personnel, and (with the aid of stage makeup) wounded victims of the attack. Use of chemical weapons in the Syrian Civil War has been confirmed by the United Nations.  Deadly attacks during the war included the Ghouta attack in the suburbs of Damascus in August 2013 and the Khan al-Assal attack in the suburbs of Aleppo in March 2013.  While no party took responsibility for the chemical attacks, the Syrian Ba'athist military was seen as main suspect, due to a large arsenal of such weapons.  A U.N. fact-finding mission and a UNHRC Commission of Inquiry have simultaneously investigated the attacks.  The U.N. mission found likely use of the nerve agent sarin in the case of Khan al-Assal (19 March 2013), Saraqib (29 April 2013), Ghouta (21 August 2013), Jobar (24 August 2013) and Ashrafiyat Sahnaya (25 August 2013).  The UNHRC commission later confirmed the use of sarin in the Khan al-Asal, Saraqib and Ghouta attacks, but did not mention the Jobar and the Ashrafiyat Sahnaya attacks.  The UNHRC commission also found that the sarin used in the Khan al-Asal attack bore "the same unique hallmarks" as the sarin used in the Ghouta attack and indicated that the perpetrators likely had access to chemicals from the Syrian Army's stockpile.  Those attacks prompted the international community to pressure disarmament of the Syrian Armed Forces from chemical weapons, which was executed during 2014.  Despite the disarmament process, dozens of incidents with suspected use of chemical weapons followed throughout Syria, mainly blamed on Syrian Ba'athist forces, as well as the Islamic State of Iraq and the Levant and even on Syrian opposition forces. The Islamic Jihad Organization – IJO (Arabic: حركة الجهاد الإسلامي‎ ‎ , "Harakat al-Jihad al-Islami") or Organisation du Jihad Islamique (OJI) in French, but best known as "Islamic Jihad" (Arabic: "Jihad al-Islami") for short, was a Shia Islamist militia known for its activities in the 1980s during the Lebanese Civil War.  They demanded the departure of all Americans from Lebanon and took responsibility for a number of kidnappings, assassinations, and bombings of embassies and peacekeeping troops which killed several hundred people.  Their deadliest attacks were in 1983, when they carried out bombing of the barracks of French and U.S. MNF peacekeeping troops, and of the United States embassy in Beirut. The Greysteel massacre was a mass shooting that happened on the evening of 30 October 1993 in Greysteel, County Londonderry, Northern Ireland.  Three members of the Ulster Defence Association (UDA), a loyalist paramilitary group, opened fire in a crowded pub during a Halloween party, killing eight civilians and wounding thirteen.  The pub was in an Irish Catholic and Irish nationalist area.  The group claimed responsibility using their cover name "Ulster Freedom Fighters" and said that the attack was revenge for the Shankill Road bombing by the Provisional IRA a week earlier. On November 5, 2009, a mass shooting took place at Fort Hood, near Killeen, Texas.  Nidal Hasan, a U.S. Army major and psychiatrist, fatally shot 13 people and injured more than 30 others.  The shooting was the worst mass shooting on an American military base.
Answer: Provisional Irish Republican Army