The Somali radical group Al-Shabaab gunmen on Thursday morning attacked the Moi University's College in Kenya's eastern town of Garissa, leaving at least 147 people dead and more than hundred students still missing so far.
The attack was the worst since Kenya sent troops across the border into Somalia in October 2011.
Following are the major terror attacks worldwide in the past two decades.
January 2015 -- Twelve people were killed and 11 others injured when masked gunmen stormed the offices of Charlie Hebdo in Paris on Jan. 7, 2015.
Al-Qaeda in the Arabian Peninsula (AQAP) claimed responsibility later in an video for the rampage at the French newspaper.
April 2014 -- At least 75 people were killed and 215 others injured in an explosion which rocked a large motor park in Nigeria's capital city Abuja on April 14, 2014.
Nigerian officials blamed the explosion on Boko Haram, a sect which has proved to be a major security threat in the West African country since 2009.
September 2013 -- At least 67 people died and 175 others were seriously injured in a four-day siege at the Westgate Shopping mall in Kenya's capital city. The massacre was also carried out by Al-Shabaab fighters.
May 2013 -- A wave of bombing attacks struck war-torn Iraq on May 17, 2013, leaving at least 73 people dead and 148 others wounded.
July 2012 -- More than 100 people died and 200 others were injured in about 30 terror attacks on July 23, 2012, making the day the bloodiest since August 2011.
July 22, 2011 -- Up to 76 people were killed and more than 80 others injured in a bombing in Oslo, Norway, and a shooting rampage on the nearby island of Utoya.
May 2010 -- Bombers and gunmen killed 114 people on May 10, 2010 in a wave of attacks on markets, a textile factory, checkpoints and other sites across Iraq.
October 2009 -- Two suicide bombs tore through downtown Baghdad on Oct. 25, 2009, killing at least 132 people.
November 2008 -- Armed terrorists launched coordinated attacks in Mumbai, India on Nov. 26-27, 2008, killing at least 195 people, including the head of Mumbai's anti-terrorist squad.