The Movement for Emancipation of Niger Delta will attack mosques, Islamic institutions and some clerics in what the group called "Operation Barbarosa," the Nigerian Tribune reported Monday.
In a statement "on behalf of the hapless Christian population in Nigeria, " the movement said it would start "a crusade to save Christianity in Nigeria from annihilation."
The group said it would bomb "mosques, hajj camps, Islamic institutions, large congregations in Islamic events" and assassinate "clerics that propagate doctrines of hate."
The bombings would begin May 31, the statement said.
The campaign of violence could only be stopped, the group, known as MEND, said, if Christian religious leaders and Henry Okah, the imprisoned leader of MEND, intervened or if Boko Haram leaders issued assurances that hostilities against Christians would end.
The Joint Task Force, a Nigerian military unit that targets Boko Haram, denounced the statement, saying MEND no longer existed.
"Those attempting to christen themselves MEND today are impostors and a bundle of 'never-do-wells' who want to be accorded undue recognition at the expense of the peace currently savored in the Niger Delta," said Lt. Col. Onyema Nwachukwa, a JTF spokesman.