MAIDUGURI, Nigeria -- Boko Haram militants Friday slit the throats of 11 alleged "traitors," witnesses said in the first news of desertions from the Nigerian Islamic extremist group.

The militants arrived before dawn and went door to door in northeastern Miringa town, said resident Muhammad Kimba.

"They actually dragged out 11 persons to the Eid praying ground outside the town and slaughtered all of them," said Kimba.

It is the fifth attack in a week that left 173 people killed as Boko Haram Islamic extremists appear to obey an Islamic State group order to step up attacks in the holy month of Ramadan. Boko Haram became the IS group's West Africa franchise earlier this year.

On Thursday, a woman and a girl strapped with explosives blew up and killed 13 people at a crowded market and a military checkpoint in Malari village, just outside Maiduguri city, according to security guard Abba Shehu.

In the most deadly attack, the militants targeted several mosques in Kukawa town on Wednesday, gunning down nearly 100 praying worshippers. Kukawa is 180 kilometres (110 miles) northeast of Maiduguri.

The militants, who want to impose their strict version of Shariah law across Nigeria, often defile mosques where clerics preach against their extremism. While they also have attacked churches, many more Muslims are among an estimated 13,000 people killed in the 6-year-old Islamic uprising. Another 1.5 million people have been driven from their homes.

Boko Haram took over a large swath of northeastern Nigeria last year and stepped up cross-border raids. A multinational army from Nigeria and its neighbours forced the militants out of towns, but bombings and village attacks are increasing.

President Muhammadu Buhari condemned the latest attacks, calling them "desperate acts" that underscore the need to speed up full deployment of the multinational army.