LAGOS, Nigeria - An "alarming spike" in suicide bombings by girls and women used by Boko Haram in northeastern Nigeria has children in danger of being seen as potential threats, the U.N. children's agency said Tuesday.

The number of reported suicide attacks has jumped, to 27 in the first five months of this year compared to 26 all of last year, it said.

Women and children carried out three-quarters of all such attacks with girls aged between approximately 7 and 17 years blamed for nine suicide bombings since July, UNICEF said in a collation of reports.

"Children are not instigating these suicide attacks; they are used intentionally by adults in the most horrific way," said Jean Gough, UNICEF representative in Nigeria. "They are first and foremost victims _ not perpetrators."

The agency is concerned children will increasingly be perceived as "potential threats," putting them in danger of retaliation and jeopardizing their return home.

It's not known how many thousands of children and women have been kidnapped by Boko Haram, with new abductions reported every week. UNICEF said it estimates that 743,000 children have been uprooted by the nearly 6-year-old Islamic uprising, with as many as 10,000 separated from their families in the chaos.

Nigeria's military recently reported rescuing some 700 women and children from Boko Haram during a weeks-long offensive to oust the extremists from camps in its Sambisa Forest stronghold.

Reporters have seen only 275 of those freed taken to the safety of a refugee camp on May 2 and then reportedly flown to an unidentified military facility last week, supposedly to undergo more trauma counseling.

Seventy percent of that group is children under age 5, with 63 unable to identify relatives, the National Emergency Management Agency said Sunday.

Last week, the president of the International Committee of the Red Cross, Peter Maurer, expressed alarm at "the horrific mental and physical scars" inflicted by Boko Haram violence.

"Whole communities have fled their villages and endured unimaginable suffering. Traumatized people, without homes, belongings, income and education for their children," he said, adding the massive humanitarian needs demand serious international attention.