The parents of 219 girls kidnapped by Boko Haram in Nigeria are considering whether to hold funerals to mourn their loss, UN education envoy Gordon Brown said Thursday.

“It’s a Nigerian custom that if people are missing for four months or more, then closure is required, funerals take place, a period of mourning happens,” the former British prime minister told reporters at the United Nations.

“And this, tragically, is what is happening to parents in Nigeria who are giving up hope that the children will be returned to them.”

The abducted school girls: they have been away for more than five months

In April, extremist group Boko Haram abducted 276 girls from their school dormitories in Borno state in northern Nigeria. A total of 219 are still missing.

The mass abduction triggered global condemnation and a social media campaign that forced Nigeria into accepting foreign help to locate their whereabouts.

Brown said he did not want the funerals to take place and as there is every hope that the girls will one day return to their parents.

“All the information we have is that they are likely to be alive,” he said.

The Nigerian government had been “unfairly criticized,” Brown said and was “doing everything in their power to recover the girls.”

Brown, who wants to make education compulsory for children all over the world, said 58 million children are out of school and that 10 million girls are married off each year as child brides.

He called for additional funding of $6 billion to help achieve 100 percent universal enrolment by the end of 2015.

Educating children would deprive extremist organizations of a fertile recruiting ground, he said.

Brown said the world had failed to marshall resources to get nearly 400,000 Syrian children in school this term in Lebanon, leaving them prey to extremist recruitment, trafficking, child labor and marriage.

Yet he said there was a global youth movement emerging to secure a right to an education. “I think people 100 years from now will see a global civil rights struggle underway,” he said.