Terrorists are counting on sowing hatred in deeply divided places like the city of Jos, which has long been a flashpoint for ethnic tensions.
Air raids using barrel bombs in Syria's second city of Aleppo have killed at least 76 people, including 28 children.
The United States has condemned the perpetrators of deadly attacks in Iraq as "enemies of Islam" and called the acts "cowardly".
A suicide bomber has targeted an election rally organised by a religious party in Pakistan, killing 25 people, officials say.
VIDEO: Footage by Human Rights Watch in Syria shows the government allegedly blowing up civilian hospitals and bread lines.
A bomb has killed eight people in Pakistan, including the son of an Afghan cleric, and wounded about 45 in the city of Peshawar, officials have said.
A suspect in the shooting of an MIT guard is dead, and a manhunt is on for another - both of whom are believed to be involved in the Boston bombings.
The bombs at the Boston Marathon killed three people and wounded more than 170. Here are the stories of those killed and some of the injured.
The explosives detonated at the Boston Marathon were homemade devices full of nails, possibly packed into kitchen pressure cookers, say US officials.
Two bombs have gone off at the finish line of the Boston Marathon, killing three people and injuring over a hundred. Two South Africans have been hurt.
SA athlete Rene Kalmer says she has not heard of South African casualties at the Boston Marathon after blasts at the finish line killed three people.
Twelve people were killed when an explosion rocked a government-held district of the disputed Syrian city of Aleppo, a monitoring group said.
The attacks by Islamist hardliners on tombs and mosques is ratcheting up the pressure in the south of Mali. Monica Mark reports.
Nigerian authorities say the man behind the attack on UN headquarters in Abuja last week is the al-Qaeda-linked Boko Haram sect's Mamman Nur.
A series of attacks against police in the disputed northern Iraqi city of Kirkuk on Thursday killed at least 25 people and wounded 79 others.
Kenyan police intensified security following an explosion at a Nairobi bus station which killed three people and injured dozens of others.
An announcement this week linking Henry Okah to a car bomb explosion in Warri in March could deal a fresh blow to his bail application in SA.
A bomb blast killed about 40 worshippers attending Friday prayers at a mosque in a restive area of north-west Pakistan.