Authorities in Nigeria and the United States are investigating an attack on a U.S. convoy in southeast Anambra state on Tuesday. The assailants, and armed men, killed two consulate staff and two policemen while abducting two police officers and a driver.

Tochukwu Ikenga, the spokesperson for the Anambra state police command, announced on Wednesday that security forces are currently searching for the perpetrators and the three abducted individuals.

In a separate statement released late Tuesday, Ikenga noted that local police had no prior knowledge of the movement of the U.S. convoy until after the attack noting that the area where the incident occurred is known for separatist violence.