The ruthless slaughter of Christians continues unabated.

YOLA, Nigeria (Reuters) – Attackers armed with guns and explosives killed 22 people at a busy church service in a northeast Nigerian village, witnesses said on Monday, in a region where Islamist sect Boko Haram is resisting a military crackdown.

They set off bombs and fired into the congregation in the Catholic church in Waga Chakawa village in Adamawa state on Sunday morning, before burning houses and taking residents hostage during a four-hour siege, witnesses said.

President Goodluck Jonathan is struggling to contain Boko Haram in remote rural regions in the country’s northeast corner, where the sect first launched an uprising in 2009.

The shady sect, which wants to impose sharia law on a country split roughly equally between Christians and Muslims, has killed thousands over the past four and a half years and is considered the biggest security risk in Africa’s top oil exporter and second largest economy after South Africa.

Its fighters’ favorite targets have traditionally been security forces, politicians who oppose them and Christian minorities in the largely Muslim north.