Among the at least 64 people killed in the two devastating blasts that tore through outdoor gatherings in Uganda where hundreds of soccer fans were in the midst of watching the World Cup final was 25-year-old American Nate Henn.
Henn worked for a California-based children's charity, Invisible Children, which helps former child soldiers in Uganda.
The selection of targets in the Ugandan capital of Kampala -- a restaurant and a sports field where people were watching the game on large-screen TVs -- ensured the bombs struck a broad mix of Ugandans and foreigners, including Americans.
The wounded were rushed to local hospitals, which were soon overwhelmed. Fred Opolot, a Uganda Media Center spokesman, said, "The government of Uganda ladies and gentlemen does convey its condolences to the bereaved families and requests the public to remain calm under this situation, thank you very much."
Police said initial signs indicated bombs had been placed under tables, though investigators had not yet ruled out suicide bombers.
"Right now it is too early to say we have suspects because it could be a suicide bomber or a time bomb, so it is too early to speculate and conclude that they were suicide bombers. Let's give time to our investigators. They will be able to give us a full report of their findings," Capt. Judith Nabakooba, a police spokeswoman, said.
Al Shabaab, a fundemental Islamist group based in Somalia, today claimed responsibility for the attacks.
"We will carry out attacks against our enemy wherever they are," Sheik Ali Mohamud Rage speaking from Mogadishu told The Associated Press.
"No one will deter us from performing our Islamic duty."
Intelligence officials had previously told ABC News there's evidence the attack was carried out by the Al Shabaab terror group.
During a recent trip inside Somalia for ABC News, we came face-to-face with Al Shabaab terrorists. At a prison in the northern Somali capital of Bosasso, captured militants threw rocks and shouted angrily at us when they found out we were Americans.
When I asked one of them why people join Al Shabaab, accused terrorist Mohammad Amin Omar told me, "We're fighting to bring Islamic law to their country, because we are Muslims and it is according to the Koran."
Somali officials had long warned the group had both the ambition and ability to stage attacks outside Somalia. This appears to be the proof.
Intelligence officials had been tracking a cell of suicide bombers targeting Uganda, as well as Kenya and Burundi, in retaliation for a new offensive launched against Al Shabaab led by the Somali government and supported by African peacekeepers. All three of those countries are now on high alert.