Pakistani Interior Minister Rehman Malik confirmed that a Dec. 28 explosion in Karachi, which killed approximately 20 people taking part in a Muharram procession, was the work of a suicide bomber. Similar attacks preceded the bombing. On Dec. 26, an explosive device concealed in a parked car detonated as Muharram mourners passed by, wounding 13 people. On Dec. 27, 30 people taking part in a Shiite procession were injured when an explosion occurred nearby — authorities initially blamed the blast on a gas leak but later confirmed that an explosive device had been planted on a manhole cover. Karachi is a strategic target for militants; its port is vital to Pakistan's economy and is the country's entry point for U.S. and NATO supplies destined for Afghanistan. Unrest on a large enough scale in the city would be felt throughout the country and by U.S. and NATO forces fighting in Afghanistan. Following the Dec. 28 attack, Karachi residents — angry at the state's inability to secure the population — erupted into violent protests, with rioters setting fires to parked cars and shops and attacking police. Attacks such as the ones over the past three days are designed to trigger Shia-Sunni sectarian violence as well ethnic clashes between the Muhajirs, who have traditionally ruled Karachi and urban areas of Sindh province, and a sizable Pashtun minority that has migrated to the city from northwestern Pakistan. Protests and riots resulting from the Dec. 28 suicide bombing are an indication of what to expect should attacks continue. Explosions are rare in Karachi — a relatively peaceful city that has avoided the daily attacks occurring farther north and west in cities like Islamabad, Lahore and Peshawar. Geographically, Karachi is much farther from the traditional Islamist militant sanctuaries in the Federally Administered Tribal Areas, where Pakistani military forces are combating militant Islamists. However, STRATFOR has noted that militants have begun shifting their targets farther south in recent weeks, with Islamist militants striking in Multan on Dec. 9 and in Dera Ghazi Khan on Dec. 15. This string of violence is the first indication that attacks have spread to Pakistan’s southern port. The presence of Islamist militants in Karachi is a long-known fact, but groups such as Tehrik-i-Taliban Pakistan and their proxies in Karachi, such as Lashkar-e-Jhangvi, have not yet exploited their assets there. The first 10 days of Muharram offer militants a target-rich environment in the form of large groups of Shia walking through the streets as part of the mourning ritual. An attack during Muharram allows Islamist militants the most leverage over their assets in Karachi, since the targets are soft and contentious. It makes sense that the attacks would come during the mourning period, when sectarian tensions are at an all-time high between Sunnis and Shia. (click image to enlarge) Karachi's government, which is dominated by a single political party — the Muttahida Quami Movement (MQM) — has a tight grip over the city and engages in its own violent tactics to maintain control. The emergence of a competing force such as a militant Islamist movement threatens the MQM, and likely will elicit a strong response. MQM leader Altaf Hussain appealed for a strengthening of Karachi's government following the attacks in order to handle militant threats on its own, a clear illustration of how the MQM could use these attacks to protect its turf and even try to further enhance its power over Karachi. While the fallout from recent attacks has led to mild protests (something Karachi and its local government are used to), they likely could have been much worse, had militants struck earlier in the month of Muharram and maintained an aggressive tempo. The fact that militants struck only at the end of the mourning period demonstrates an operational limitation on their ability to carry out a longer campaign in Karachi – something that they have been able to do farther north and west. It is unclear if militants in Karachi have the capability to continue these attacks. If they do carry out a drawn-out campaign, unrest in Karachi is likely to escalate. But with the most vulnerable time period of Muharram now over, attacks would not be as well-leveraged as they would have been had they occurred during the initial days of Muharram. By carrying out attacks in Karachi, Islamist militants likely have created the perception that they can strike anywhere in Pakistan. It remains to be seen how long militants can sustain these attacks, however, and the timing of the attacks failed to fully exploit the mourning period of Muharram.