"Some arrests have been made. Some died in the process. Some were suicide bombers," Jonathan said in a BBC interview during a visit to Kano, the largest city in Nigeria`s mainly Muslim north.
"There must be people who are sponsoring them. Terrorists all over the world have their source of income," he said.
"We are also looking into those areas to make sure that the so-called Boko Haram... those who are encouraging them, those who are sponsoring them, shall be brought to book."
Asked about numbers of Boko Haram members, he said: "Nobody can say for now, because you know that they are not organised armed forces."
Coordinated bombings and gun battles rocked Kano after Friday prayers in attacks claimed by Boko Haram that targeted a police headquarters and other police stations, a secret police building and immigration offices.
Gunfire also erupted in several areas of the city, which had escaped the worst of the violence blamed on the Islamist group in recent months.
(M014)
Editor: Ella Syafputri
Copyright © ANTARA 2012
