Israeli athletes were attacked during the 1972 Munich Olympics
Previous attacks on sports events, and failed plots, in recent decades, after Monday's bomb blasts that killed three people at the Boston Marathon:
September 5, 1972 - Eight members of the Palestine Liberation Organisation (PLO) splinter group Black September raided the Israeli team's quarters in the Olympic village in Munich, killing a weightlifter and a wrestling coach almost immediately.
They took nine athletes and officials hostage and demanded the release of more than 200 prisoners held in Israel. Later, at Munich's military airport, from where the guerrillas were hoping to leave Germany, police opened fire and a gunfight erupted. All the hostages were killed and five of the gunmen and a policeman also died.
Image: On the eve of the start of the Munich Olympics, the Israeli team visits the site of the concentration camp at Dachau in southern Germany, on August 25, 1972. Eleven members of the team were later killed in a terrorist attack at the Games on September 6, 1972.
Photographs: Keystone/Hulton Archive/Getty Images
Powerful bomb exploded in the Olympic Park in Atlanta
July 1996 - A powerful nail bomb exploded in Centennial Olympic Park on July 27 during the Atlanta Olympics. One person died and more than 100 were hurt. Eric Rudolph, who was sentenced to three life terms without parole in 2005 for Atlanta and other bombings, said the Olympic attack was designed to "confound, anger and embarrass the Washington government in the eyes of the world for its abominable sanctioning of abortion on demand".
June 1998 - An Algerian cell funded by Osama bin Laden planned to attack the World Cup finals in France, targeting the US Embassy in Paris and the US soccer team. The cell also planned a pitch assault on the England team during their group match against Tunisia in Marseilles. Individuals were arrested by French intelligence, foiling the plot.
Image: Debris surrounds the base of the sound tower, the scene of a bomb blast near the AT & T Pavillion in Centennial Olympic Park during the 1996 Centennial Olympic Games in Atlanta, Georgia, on July 27, 1996.
Photographs: Gray Mort/Getty Images
New Zealand called off Pakistan tour after bomb blast in Karachi
May 2002 - A car bomb exploded in the Pakistani city of Karachi near the hotel where the New Zealand cricket team were staying, killing 13 people including 11 French navy experts. New Zealand called off the tour after the attack.
2002 - Khalid Sheikh Mohammed, al Qaeda's operational leader who was arrested in 2003, revealed that the group had intended to carry out attacks in Japan during the soccer World Cup jointly hosted with South Korea. The attacks did not go ahead as the group failed to establish a network there.
Image: New Zealand cricket captain Stephen Fleming prepares to board a bus for the airport in Karachi on May 8, 2002.
Photographs: Zahid Hussein/Reuters
Iraqi taekwondo squad kidnapped and killed in 2006
May 26, 2006 - Gunmen killed the coach of Iraq's national tennis team and two of his players in Baghdad, days after militants issued a warning forbidding the wearing of shorts.
May 17, 2006 - Some 15 athletes and officials from a taekwondo squad were kidnapped from a highway in western Iraq as they travelled to a training course in Jordan. The decomposed bodies of at least 13 of the squad were found in the desert in June 2007.
July 16, 2006 - Up to 50 gunmen seized some 30 Iraqi sports officials, including the national Olympic chief Ahmed al-Hadjiya, and their bodyguards, in a brazen daytime raid on a central Baghdad hall. They are still missing.
Image: Iraqis carry coffins containing the remains of members of the Iraqi taekwondo national team in Baghdad, on June 16, 2007.
Photographs: Zahid Hussein/Reuters
Sri Lanka's cricket team attacked in Lahore
July 31, 2006 - Two suitcases filled with explosives were placed on trains near Hamm and Koblenz and would have killed hundreds during the soccer World Cup in Germany. The detonators were faulty and did not ignite the explosives.
March 3, 2009 - Gunmen attacked a bus carrying Sri Lanka's cricket team outside a Lahore stadium in Pakistan, killing seven people, including six policemen and a driver. Six of the cricketers and a British coach were wounded.
Image: Sri Lankan spinner Ajantha Mendis is injured during the attack on the Sri Lankan cricket team in Lahore, on March 3, 2009.
Photographs: Nir Elias/Reuters
Togo soccer team bus attacked in 2010
January 8, 2010 - A Togo soccer team bus, travelling from the Republic of Congo to the African Nations Cup in Angola, had just entered Cabinda province when it came under heavy gunfire from separatists.
Team media officer Stanislas Ocloo and assistant coach Amalete Abalo were killed. Seven people were wounded. The Front for the Liberation of the Enclave of Cabinda (FLEC), who have fought for independence in the oil-producing province, claimed responsibility.
Image: Pallbearers carry the coffin of Togo soccer team's assistant coach Amalete Abalo during the funeral service in front of Congress Palace in Lome, on January 15, 2010.
Photographs: Noel Kokou Tadegnon/Reuters