Female suicide bombers in Nigeria are reportedly now carrying babies to avoid detection in their attacks, a report has said.

According to BBC, on January 13, two women detonated their devised in a town called Madagali, killing themselves, two babies and four others.

The report said that the two managed to pass a checkpoint after they were thought to be ordinary civilians, as they carried infants.

"The two women carrying infants... were not stopped, and exploded their own devices past the security point," the report said.

Officials said the use of babies could signal a "dangerous" trend.

The incident took place just a few weeks after two girl suicide bombers blew themselves up, again at a checkpoint, outside the city of Maiduguri.

The teenagers detonated their explosives when they were stopped for a search.

Three civilians were wounded.

Boko Haram has used scores of females in suicide bombings, with suspicions that most of these women would have been kidnapped.

The group's seven-year old Islamic uprising has killed more than 20 000 people.