Terrorist attacks in Pakistan have killed more than 4,350 people in around four years, blamed on Taliban and al Qaeda-linked extremists opposed to the government's alliance with the United States.
Here is a list of major attacks since 2007:
2007: October 18: Bomb attacks targeting former prime minister Benazir Bhutto kill 139 people in Karachi as she returns to Pakistan for the first time in eight years. She is killed in another gun and suicide attack on December 27.
2008: August 21: Twin suicide attacks kill 64 people outside Pakistan's main arms factory in Wah, near Islamabad.
September 20: Sixty people are killed when a suicide truck bomb brings down part of the five-star Marriott hotel in Islamabad.
2009: October 28: A car bomb destroys a Peshawar market, killing 125 people.
2010: January 1: A suicide car bomb kills 101 people at a village volleyball game in the northwestern district of Bannu.
March 12: Twin suicide attacks on the military in Lahore kill 57.
May 28: Gun and suicide attackers storm mosques belonging to the Ahmadi religious minority in Lahore, killing 82 people.
July 9: A suicide bomber blows himself up in a busy market in the northwestern Mohmand tribal district, killing 105 people.
September 3: A suicide attack kills 59 at a Shiite Muslim rally in Quetta.
November 5: A suicide bomber kills 68 people during Friday prayers in the northwest's Darra Adam Khel area.
2011: May 13: Two suicide bombers kill at least 80 people outside a police cadet training centre in the northwestern district of Charsadda.