The leader of Nigeria’s main Islamist militant group threatened to attack oil refineries and schools in the West African nation’s mainly Christian south.

“You will in the coming days see your refineries you’re boasting about bombed,” Abubakar Shekau, the leader of Boko Haram, said in the local Hausa language, addressing residents of the oil-rich Niger River delta in a video released to reporters in the northeastern city of Maiduguri. “Our refinery is Allah.”

Boko Haram fighters will extend their attacks beyond Borno, Yobe and Adamawa, the three northeastern states where President Goodluck Jonathan declared emergency rule last year to combat the insurgents, Shekau said.

The group is “fighting Christians wherever we meet them and those who believe in democracy, those who pursue Western education,” he said.

Boko Haram, which means “Western education is a sin,” is fighting to impose Shariah, or Islamic law, in Africa’s biggest oil producer, whose 170 million population is roughly split between Christians, mainly in the south, and Muslims, mostly in the north. The US Department designated Boko Haram a “terrorist” organization in November.

At least 47 people were killed by suspected Boko Haram Islamists in the northeastern town of Bama this week, a police official said. Bama is 130 kilometers (81 miles) from Maiduguri, the Borno state capital.