The PKK took up arms against Turkey in 1984 with the aim of creating an ethnic homeland in the southeast. More than 40,000 people have been killed in the conflict since then.
Following is a chronology of some of the recent major attacks and bombings in Turkey:
November 15, 2003 - Thirty people are killed and 146 wounded when car bombs shatter two synagogues in Istanbul. Authorities name two men from southeast Turkey as the suicide bombers, saying the attacks bear the hallmarks of the al Qaeda network.
November 20, 2003 - Thirty-two people are killed and many wounded in two explosions in Istanbul. Part of the HSBC Bank headquarters is destroyed. The British consulate is damaged.
June 24, 2004 - Four people are killed and 15 wounded in an explosion in Istanbul, before former U.S. President George W. Bush was due to arrive in the city.
July 2, 2005 - Six people are killed and 15 injured after a bomb planted by Kurdish guerrillas explodes on a train between the eastern towns of Elazig and Tatvan in Bingol province.
July 6, 2005 - A bomb rips through a minibus in the western holiday resort of Kusadasi, killing at least five people, including a British woman and an Irish woman.
February 13, 2006 - Six people are injured, one seriously, after a bomb explodes at a supermarket on the European side of Istanbul. The Kurdistan Liberation Hawks (TAK) claim responsibility for the blast and pledge more attacks.
June 25, 2006 - A blast tears through a tourist area about 100 km east of the southern resort of Antalya, killing four and injuring 28. The Kurdistan Freedom Hawks (TAK), a group liked to the PKK, claims responsibility.
August 27, 2006 - Ten Britons and six Turks are wounded when their minibus is blown up in the tourist town of Marmaris on the Mediterranean coast. Five others are hurt by two other bombs.
August 28, 2006 - Three people are killed and 87 injured in a blast in Antalya, southern Turkey. The TAK claim responsibility.
September 12, 2006 - A bomb blast kills 10 people, eight of them children, near a park in Diyarbakir, the largest city of Turkey's restive, mainly Kurdish southeast region.
May 22, 2007 - Six Turks are killed in a suicide bombing at the entrance to a mall in the historic Ulus district of Ankara. Ninety-one people are injured.
September 27, 2007 - Two Turkish gendarme officers are killed when a mine laid by Kurdish separatists explodes in Bitlis province in eastern Turkey.
January 3, 2008 - A bomb attack on a military service vehicle outside a school kills at least five students and injures 110 in Diyarbakir.
May 9, 2008 - Three people are killed and five wounded when a land mine detonated by Kurdish guerrillas destroys their minibus in Batman province, southeast Turkey.
July 9, 2008 - Three police officers are killed in a shooting outside the US consulate in Istanbul.
April 29, 2009 - PKK militants detonate bomb which rips through armored vehicles on patrol, killing nine Turkish soldiers in Diyarbakir province.
May 4, 2009 - Gunmen armed with rifles and grenades attack a wedding party in southeastern Turkey on Monday, killing at least 44 people in what was linked to a feud between families.
May 31, 2010 - Six Turkish soldiers were killed and nine wounded in a rocket attack on a naval base in the Mediterranean port city of Iskenderun.
June 19, 2010 - Turkish troops and Kurdish militants clash at Semdinli near the Iraqi border in a firefight which kills 11 soldiers and 12 rebels.
Sept 16, 2010 - A roadside bomb kills 10 people and wounds three when it explodes under their minibus in Hakkari.
July 14, 2011 - Kurdish fighters kill 13 Turkish soldiers in what was worst clash since the PKK ended their latest ceasefire in February. Seven militants are also killed.
August 17, 2011 - The PKK attack a military convoy at Cukurca in southeast Turkey's Hakkari province. Eight soldiers and one member of the state-backed village guard militia are killed and 15 others are wounded.
September 20, 2011 - A car bomb explodes in a street in the capital Ankara near a neighborhood housing government buildings, killing four people and wounding 15. The TAK claim responsibility for the attack and vow to carry out more raids in Turkish cities.
September 20, 2011 - Kurdish guerrillas attack a police college in southeastern Siirt province, killing four people in a passing vehicle.
September 24, 2011 - Kurdish guerrillas armed with rocket launchers attack a police station in Siirt, killing five police officers and wounding nine.
October 18, 2011 - A roadside bomb planted by suspected Kurdish rebels exploded in the Guroymak district of southeastern Bitlis province, killing five policemen and three civilians, including a child.