Three aid workers have been released after being kidnapped by armed militants in Borno state, north-east Nigeria, on 22 December.

The UN says the humanitarians were released on Wednesday with a number of civilians.

It’s unclear whether a ransom was paid, or who carried out the abductions, but the militant group Boko Haram have been active in Borno for over a decade.

In a statement, a representative from the UN’s Office for the Coordination of Humanitarian Affairs said he remained concerned for the fate of aid worker Grace Taku abducted in July 2019, and Alice Loksha, a nurse kidnapped almost two years ago.

Both women remain in captivity.

He added that an increase in informal checkpoints in north-eastern Nigeria was putting civilians and aid workers at risk.

According to the UN, 12 humanitarians died in Nigeria in 2019, double that of the previous year.