More than 1,000 Nigerians have fled to neighbouring Niger after six people were killed in an attack on their village blamed on Islamist group Boko Haram, the United Nations said Thursday.

The 1,042 refugees crossed the northern border into the Niger region of Diffa after the November 30 attack, and have been taken in by families in two villages near the regional capital, the UN Office for the Coordination of Humanitarian Affairs (OCHA) said in a bulletin.

A teacher in the village confirmed the attack to local media. He said the attackers told villagers they were looking for “politicians” and “coldly killed” six people, including a police officer, after the victims were unable to recite verses of the Koran.

A security source said Niger’s army has deployed reinforcements along its border with Nigeria, a focus of worry for Nigerien authorities who have often assured they are taking measures to stop Boko Haram’s activities from spilling over into Niger.

Violence linked to the Boko Haram insurgency in Nigeria — a country roughly divided between a mainly Muslim north and a predominantly Christian south — is believed to have left some 3,000 people dead there since 2009, including killings by the security forces.