U.S. President Barack Obama has said that law enforcement agencies are investigating the April 16 bombings in Boston as an act of terrorism.

Speaking at the White House, the president emphasized that authorities do yet not know who carried out the attack, why it was carried out, whether it was conducted by a domestic or foreign organization, or whether the attack was the work of an individual.

“The FBI is investigating it as an act of terrorism,” Obama said. “Any time bombs are used to target innocent civilians, it is an act of terror.”

The attack occurred yesterday afternoon near the finish line of the annual Boston Marathon. So far, two people have been confirmed dead and dozens more injured.