Which countries support Boko Haram, ISWAP as Buhari calls for stop?

Which countries of the world are backing terrorist group Boko Haram and its other faction, the Islamic State in West African Province (ISWAP)?
The nagging question follows a statement by President Muhammadu Buhari, through his spokesman, Mr. Garba Shehu, that “President urged nations of the world to end all support provided to Boko Haram and Islam in West Africa, ISWA terrorist groups whose only goal is to sow death, violence and destruction in the sub-region.”
The President was reacting to the gruesome killing of Rev. Lawan Andimi, chairman of the Christian Association of Nigeria (CAN) in Michika local government area of Adamawa State, by his Boko Haram abductors.
He strongly condemned the terrorist killing, describing it as cruel, inhuman and deliberately provocative.
President Buhari this evening, according to Shehu, expressed sorrow that the terrorists went on to kill  the religious leader while giving signals at the same time of a willingness to set him free by releasing him to third parties.
President Buhari consoled the Christian community in Nigeria, the government and people of Adamawa state “and the Bishop’s family over the sad loss of the man of God and assures that terrorists will continue to pay a heavy price for their actions and would comprehensively be defeated by our determined armed forces.”