Geneva - The United Nations rights chief on Wednesday urged Nigeria to show compassion and make it easier for women and girls who became pregnant in Boko Haram captivity to access abortions.Boko Haram militants are estimated by Amnesty International to have kidnapped more than 2 000 women and girls in northeastern Nigeria since the beginning of 2014, including the 276 girls seized from their school in Chibok last year in a kidnapping that sparked global outrage."During their captivity, lasting in many cases for months or even years, women and girls have been sexually enslaved, raped and forced into so-called 'marriages'," Zeid Ra'ad Al Hussein told the UN Human Rights council in a special session on Boko Haram."Many survivors of these horrific experiences are now pregnant by their rapists... and several reportedly wish to terminate these unwanted pregnancies," he said.But in Nigeria, abortion is only legal when the life of the woman is at risk, Zeid said, warning that a lack of access would only add to the horrendous suffering the former captives had been through."I strongly urge the most compassionate possible interpretation of the current regulations in Nigeria to include the risk of suicide and risks to mental health for women and young girls who have suffered such appalling cruelty," he said.He also called on authorities to help women and girls freed from Boko Haram enslavement, who often face stigmatisation, to reintegrate into their communities. Boko Haram's insurgency, centred in northeastern Nigeria and aimed at creating a hardline Islamic state, has led to the deaths of at least 15 000 people since 2009.