01 Apr 1979 – Iran: Iran voted by national referendum to become an Islamic Republic and to approve a new democratic-theocratic hybrid constitution whereby Sayyed Ruhollah Musavi Khomeini who was an Iranian religious leader and politician became Supreme Leader of the country, in December 1979.
01 Apr 1970 – El Salvador: Popular Forces of Liberation formed.
02 Apr 1982 – United Kingdom, Argentine and the Falkland Islands: Argentinean military forces invade the United Kingdom islands known as the Falkland Islands. The Argentinean forces surrendered on the 14 Jun 1982.
02 Apr 2001 – Gaza Strip: PIJ official Muhammad Abd al-ll’al killed in Israeli rocket attack.
02 Apr 2015 – Kenya: At least 147 killed in an attack on Garissa University; al-Shabaab claimed responsibility.
03 Apr 2011 – Pakistan: Suicide bombers attack Sufi shrine in Dera Ghazi Khan, killing 50 and injuring more than 100; TTP claim responsibility.
03 Apr 2013 – Afghanistan: Thirty-four people and ten security personnel killed as Taliban forces storm courthouse in Farah.
11 Apr 1968 – Syria: Popular Front for the Liberation of Palestine-General Command founded.
14 Apr 2013 – Bahrain: Several devices explode in and around Manama; Members of 14 February Youth Coalition claim responsibility on social media sites.
14 Apr 1986 – Libya: US planes bomb Tripoli and Benghazi in retaliation for La Belle disco bombing on 4 April.
14 Apr 2014 – Nigeria: More than 250 schoolgirls kidnapped in Boko Haram attack in Chibok; group leader Abubaker Shekau claimed responsibility.
15 Apr 2013 – United States: Three killed and 264 injured when bomb explodes at Boston Marathon; Djokhar Tsarnaev arrested, Tamerlan Tsarnaev killed in manhunt.
15 Apr 2011 – Indonesia: Twenty-eight injured in Jakarta in country’s first suicide bombing inside a mosque; no claim of responsibility.
Dates are taken from the NCTC terrorist calendar and 361 Security Significant dates.