From late 2011 to 2014, Kenya experienced an upsurge in violent terrorist attacks. Kenyan government officials asserted that many of the murders and blasts were carried out by al-Shabaab in retaliation for Operation Linda Nchi, a coordinated military mission between the Somalian military and Kenyan military that began in October 2011, when troops from Kenya crossed the border into the conflict zones of southern Somalia. According to Kenyan security experts, the bulk of the attacks were increasingly carried out by radicalized Kenyan youth who were hired for the purpose. Kenya security officials also indicated that they were part of death squads, which carried out many of the killings under the orders of a government security council. By mid-2014, the cumulative attacks began affecting Kenya's tourism industry, as Western nations issued travel warnings to their citizens.

Background Since the Operation Linda Nchi began, Al-Shabaab vowed retaliation against the Kenyan authorities. At the militant group's urging, a significant and increasing number of terrorist attacks in Kenya have since been carried out by local Kenyans, many of whom are recent converts to Islam.Kenya: A new breed of terrorist is born Estimates in 2014 placed the figure of Kenyan fighters at around 25% of Al-Shabaab's total forces. Referred to as the "Kenyan Mujahideen" by Al-Shabaab's core members, the converts are typically young and overzealous, poverty making them easier targets for the outfit's recruitment activities. Because the Kenyan insurgents have a different profile from the Somali and Arab militants that allows them to blend in with the general population of Kenya, they are also often harder to track. Reports suggest that Al-Shabaab is attempting to build an even more multi-ethnic generation of fighters in the larger region. One such recent convert who helped carry out the Kampala bombings but now cooperates with the Kenyan police believes that in doing so, the group is essentially trying to use local Kenyans to do its "dirty work" for it while its core members escape unscathed. According to diplomats, Muslim areas in coastal Kenya and Tanzania, such as Mombasa and Zanzibar, are also especially vulnerable for recruitment.

In December 2014, Kenyan Anti-Terrorism Police Unit officers confessed to Al-Jazeera that they were responsible for almost 500 of the extrajudicial killings. The murders reportedly totaled several hundred homicides every year. They included the assassination of Abubaker Shariff Ahmed "Makaburi", an Al-Shabaab associate from Kenya, who was among 21 Muslim radicals allegedly murdered by the Kenyan police since 2012. According to the agents, they resorted to killing after the Kenyan police could not successfully prosecute terror suspects. In doing so, the officers indicated that they were acting on the direct orders of Kenya's National Security Council, which consisted of the Kenyan President, Deputy President, Chief of the Defence Forces, Inspector General of Police, National Security Intelligence Service Director, Cabinet Secretary of Interior, and Principal Secretary of Interior. Kenyan President Uhuru Kenyatta and the National Security Council of Kenya members denied operating an extrajudicial assassination program. Additionally, the officers suggested that Western security agencies provided intelligence for the program, including the whereabouts and activities of government targets. They asserted that Britain supplied further logistics in the form of equipment and training. One Kenyan officer within the council's General Service Unit also indicated that Israeli instructors taught them how to kill. The head of the International Bar Association, Mark Ellis, cautioned that any such involvement by foreign nations would constitute a breach of international law. The United Kingdom and Israel denied participation in the Kenyan National Security Council's reported death squads, with the UK Foreign Office indicating that it had approached the Kenyan authorities over the charges.

By May 2014, the United States, United Kingdom, France and Australia began issuing travel warnings to their citizens in Kenya. This had an immediate impact on Kenya's tourism industry, as European visitors left the country and hotel establishments were consequently forced to lay off staff. The U.S. also reduced its staff levels at its Nairobi embassy. In June 2014, the U.K. likewise shut down its Honorary Consulate in Mombasa over security concerns.

Timeline

2011 The first attack by al-Shabaab was on a blue-collar bar known as Mwaura's in downtown Mfangano Street in Nairobi on Monday, 24 October 2011, at around 1:15 am. The hurled grenade left one person dead and wounded more than 20. Police said that the weapon used was a Russian-made F1 grenade.

A second blast occurred later the same day, when a grenade was tossed out of a moving vehicle into the Machakos bus terminus. 59 men and ten women were subsequently hospitalised, of which two were in intensive care and five people were confirmed dead.

The attacks came only two days after the United States warned of "imminent" terror attacks. The US warning had implied that al-Shabaab would carry out reprisals in response to Kenyan troops' incursion into Somalia in mid-October. Elgiva Bwire Oliacha, a recent Kenyan Muslim convert, was arrested in connection with the two blasts and was sentenced to life in prison after having pleaded guilty to all charges.

Al-Shabaab was suspected of carrying out a few more attacks in October as well. In November 2011, Al-Shabaab attacked several other locations including the East African Pentecostal Church, a military convoy, and a Holiday Inn hotel. The militant group is suspected of carrying out nine attacks in Kenya in December 2011; some of the attacks resulted in injuries and casualties while some resulted in no injuries.

2012

January – June Militants were responsible for several attacks over the first few months of 2012. In January, there were three reported attacks, including the killing of the chairperson of the Community Peace and Security Team in Hagadera camp as well as several police officers. It was also reported that Kenyan police seized explosive equipment in an Ifo camp in the Dadaab complex, arresting nine suspects. In February, Al-Shabaab claimed responsibility for an attack that resulted in the death of a police officer and a civilian while injuring two other civilians. On 10 March 2012, six were killed and over sixty were injured after four grenades were thrown into a Machakos bus station in Nairobi.

On Sunday, 29 April 2012, around 8:50am, an attack took place at God's House of Miracles Church at Ngara Estate in Nairobi. As reported by one of the dailies, an attacker, who goes by the name Amar, entered the church and left. He later came back and took a seat in the back, hurling the grenade at worshipers while they had been called by the pastor to the pulpit. The experts said that the grenade used had been made in China.

One person died and 11 people were admitted at Kenyatta National Hospital.

On Tuesday, 15 May, three hand grenades were hurled at the Bella Vista nightclub in Mombasa, Kenya, killing one and leaving five others injured. The attacker also fired indiscriminately after he was denied entry into the Bella Vista club. A woman died as a result of a gunshot to the chest the two guards were injured. A suspect who had sustained injuries in the attack was arrested in connection to the assault. A bus ticket to Nairobi was recovered from the suspect and a magazine loaded with eight rounds of ammunition. Police arrested a suspect Mr. Thabit Jamaldin Yahya. He is still in remand.

On Monday, 28 May, a blast went off from inside the Sasa Boutique located within Assanand's House on Nairobi's Moi Avenue. 27 people were injured in the blast, and it was reported that four were in critical condition. Police Commissioner Mathew Iteere said that the explosion was the result of either a grenade or a bomb. Over the course of four other May attacks, one police officer was killed and numerous others were injured.

On Sunday, 24 June at around 10 pm EAT, another grenade attack was reported at a Jericho Beer Garden in Mishomoroni, Kisauni Constituency in Mombasa, Kenya. The bar was packed with patrons who had gathered to watch the UEFA European Championships 2012 football match between England and Italy. The grenade killed one person on the spot while two more died due to injuries while they were receiving treatment at the Coast general hospital. 30 more were injured, including a suspect who was alleged to be part of the attackers, a 9-year-old boy.

This attack happened on the same day the Kenyan Navy had taken away two explosive devices that had been found floating in the Indian Ocean. The US government (through its embassy in Kenya) had issued a warning to its citizens to leave the coastal city of Mombasa due to a possible imminent attack. Athman Salim, a 23-year-old Kenyan day labourer from the Kilifi District was the main suspect of the attack. Although a Muslim, Athman denied any involvement with extremist groups or having ever journeyed to Somalia. He claimed that he had visited the pub to listen some local music, and indicated that he had never worked outside the city of Mombasa. He was released on 9 July after spending 10 days in Nyali police station.

July – December On 1 July at around 10:15 am EAT, masked gunmen attacked two churches (the Central Catholic Cathedral and AIC churches) simultaneously in Garissa, located approximately 140 kilometres from the Somali border. The assailants killed seventeen people and left fifty injured. The churches are 3 kilometres apart and the dead included two police officers, four men, nine women and two children. The North Eastern Police Provincial Officer (PPO) Philip Ndolo reported that the gunmen attacked the two policemen first and took their firearms before they proceeded to attack the churches. The attackers used pistols to shoot the policemen at point blank range and then snatched their G3 rifles which were later used to shoot at the AIC church worshipers indiscriminately. No shooting was reported at the Catholic's Central Cathedral but a hand grenade was set off, resulting in less casualties than the AIC attack. The Supreme Muslim Council (SUPKEM) in Kenya warned of a misinterpretation of this attack as a religious war against the Christians. A joint effort by the Kenya Police, Administration Police, National Security Intelligence Service and the paramilitary General Service Unit saw the arrest of 83 suspects in connection with the attack during a massive security swoop after the attack.

Four people were reported injured on 18 July when two hand grenades went off at a barbershop in Wajir. In addition, three police officers were injured on 25 July when their patrol hit a landmine.

Police also arrested a man who was carrying two grenades at the Nakuru Agricultural Show shortly before President Mwai Kibaki arrived to deliver a speech. It was also reported that they arrested two men with four hand grenades in Kitale as they were boarding a Nairobi-bound bus; a third man escaped capture.