Hezbollah began using tactic in the 1980s, Tamil Tiger fighters adopted it during the country's 26-year civil war, and method was later embraced by Palestinians

President gives military wider berth on detentions, restoring civil war-era powers; Tuesday declared a day of mourning

At least four Americans killed in bombings; Washington sends FBI agents to assist local police in investigation

Foreign Ministry warning comes as island nation blocks access to most social media, following deadly bombings that killed nearly 300 people

Agencies alerted country to threat several times, starting on April 4; political dysfunction blamed for keeping PM, ministers in dark

No injuries reported when van parked outside St. Anthony's explodes; president gives army wartime powers for manhunt

National Thowheeth Jama'ath was previously known for smashing Buddhist statues; presidency says international terror groups supported local branch

Earlier, Colombo police say they located 87 bomb detonators at a bus stop in the city, a day after series of blasts killed at least 290

All seven suicide bombers identified as citizens and members of National Thowfeek Jamaath, which has suspected foreign links; death toll rises to 290

Forensic crime analyst says seven people carried out attacks on hotels and churches; two later bombings still under investigation