Unidentified assailants in Niger attacked soldiers guarding a major Niger-Benin oil pipeline on Wednesday, killing six soldiers, three security sources told Reuters on Thursday.

The pipeline was not damaged, one source said.

The attack against the patrol tasked with protecting the pipeline took place between the villages of Salkam and Tibiri, in Niger’s southeastern Dosso region, on Wednesday afternoon, one source said.

No one has yet claimed responsibility for the attack, which is the first on security forces protecting the pipeline. Jihadist groups linked to al Qaeda and Islamic State operate in the area.

All three sources said six soldiers were killed.

The nearly 2,000 km (1,243-mile) PetroChina backed pipeline was officially launched in November linking Niger’s Agadem oilfield to Benin’s coast where the crude oil is loaded for export. (Reuters: Text, Excluding Headline)