Two female suicide bombers, suspected to be affiliated with Boko Haram, killed at least 60 people when they blew themselves up at a refugee camp in the northeastern Nigerian town of Dikwa, health and rescue officials said Wednesday.

The attack occurred 50 miles outside the capital of Borno state when the female suicide bombers snuck inside the camp and blew themselves up inside the internally displaced persons camp, reported Reuters, citing emergency officials. The incident reportedly took place on Tuesday, but it was only made public Wednesday due to a breakdown in the telephone system.

Officials noted that 78 others were injured in the attack and are being treated for wounds.

No group has claimed responsibility for the attack, but officials have blamed the incident on the Boko Haram which frequently uses women and even children to carry out their attacks, according to The Independent.

Boko Haram, which recently overtook ISIS as the deadliest militant group, has killed 20,000 people and left 2.5 million others homeless throughout the course of its 6-year insurgency.

Since troops from Nigeria, Chad and Cameroon drove the extremists from various towns and villages where they announced their Islamic caliphate, they have reverted to attacking areas where groups of people gather such as places of worship and marketplaces, according to CBS News.

Even with their new m.o., the group has only rarely targeted camps housing those displaced by the conflict, and Tuesday's attack was the first to leave casualties in Borno state.