The UN’s human rights chief has said his office has received reports that Boko Haram fighters retreating from advancing military forces in Nigeria murdered women and girls they had taken as “wives”, along with other captives.

More than 6,000 people have died in eastern Ukraine since the start of the conflict almost a year ago, the UN human rights office says.

The fighting in eastern Ukraine has killed nearly 300 people in the last month despite a ceasefire and has violated people’s rights so much it could amount to war crimes, UN rights investigators said.