Two suspected child suicide bombers struck at a marketplace in Nigeria's Yobe state on Sunday, killing at least four people and injuring others, as Boko Haram continues its horrific new tactic of using young girls as suicide bombers.
This was the second such attack in as many days wherein girls, as young as 10, have blown themselves up.
"I saw their dead bodies. They are two young girls of about 10 years of age ... you only see the plaited hair and part of the upper torso," a witness of the Sunday bombing told Reuters.
Some reports suggest that one of the bombers was older and in her twenties.
The market blasts came a day after a 10-year-old girl fitted with a bomb killed 19 people in Maidguri in Borno State on Saturday.
While Boko Haram has been known to use female suicide bombers, its new tactic of using young girls strapped with devices has revealed the brutality of the terror group, which has ravaged the north-east of the country in its quest to form an Islamic state.
Last July, a female suicide bomber had struck in the state of Gombe, and soon after a 10-year-old girl was found wearing a suicide vest.
According to experts, while the older women are ideologically motivated into carrying out the attacks, the younger girls may be forced or tricked into donning suicide vests.
The young girls, often kidnapped, are unaware of the group using them as human bombs.
"This girl may not necessarily know she was conveying a timed bomb. The girl was torn into two halves, and half of her body was thrown across buildings by the devastating blast," one of the witnesses from the Maidguri bombing told The New York Times.
In Sunday's twin bombing, a security official told AFP that after the first girl's explosives went off, "the second bomber was terrified by the explosion and she tried to dash across the road but she also exploded".
Security officials have described the attacks as "new and disturbing."
"It's something quite new, and it's disturbing, using these young, young girls wearing hijabs. Now, one has to be suspicious of any lady wearing a hijab — whether it's a young lady, or an old lady," a police official told NYT.
A witness told Nigeria's The Guardian that the young girls came to the market on tricycles.
"When two female suicide bombers on tricycles reached the market entrance, one of them alighted and went inside the market. The other was left in the tricycle, before the explosives were detonated simultaneously," a local told the Nigerian newspaper.
The use of such young girls for bombing attacks "should be searing the conscience of the world", UNICEF executive director Anthony Lake has said.
"Words alone can neither express our outrage nor ease the agony of all those suffering from the constant violence in northern Nigeria," Lake said.