A wave of bloody massacres and attacks has taken place since the revolt against Syrian President Bashar al-Assad's regime broke out on March 15, 2011:
March 23: At least 100 people killed by security forces during demonstrations in the southern town of Daraa, cradle of the uprising, activists and witnesses say.
July 31: About 100 people reported killed in a huge army offensive in the protest hub of Hama in central Syria.
December 23: Suicide bombers blow up two vehicles at a security premises in Damascus, killing 44 people including both civilians and security personnel.
February 4: More than 230 civilians, including dozens of women and children, killed in an army onslaught on the central city of Homs.
May 10: 55 killed when two blasts hit a Damascus highway during morning rush hour near a security premises.
May 25: At least 108 killed, including 49 children and 34 women, in regime shelling of Houla in Homs province.
July 12: More than 150 people reported massacred by regime forces in the Hama province village of Treimsa.
July 18: Four senior security officials, including Assad's brother-in-law Assef Shawkat, killed in a Damascus bombing.
August 26: Rebels announce the discovery of at least 320 bodies in Daraya near Damascus after a six-day assault by pro-government forces. Dozens more bodies found later, bringing to more than 500 the number of civilians killed.
October 3: More than 60 killed, mostly civilians, in car bombings in second city Aleppo.
November 5: A suicide car bombing in Hama province kills at least 50 soldiers and pro-regime fighters.
November 28: A double car-bombing in Jaramana near Damascus kills 54.
January 15: 87 killed in explosions at Aleppo University.
106 killed in an army assault on Homs.
January 24: A suicide car bombing at a military intelligence headquarters in Damascus province kills 53 people, the Observatory reports on February 1.
January 29: The bodies of nearly 80 young men, all executed, found in a river in Aleppo.
February 21: Car bombings in Damascus kill at least 83 people, including more than 60 in an attack near the headquarters of the ruling Baath party.