British BP and the Norwegian oil company, Statoil, have temporarily removed their staff from two natural gas facilities in Algeria – Salah Gas and In Amenas – after al-Qaeda-linked militants attacked the former, Middle East Eye reported.

The attack occurred at the Krechba gas plant, operated jointly by the two and the Algerian national oil company Sonatrach. The plant is an extension of the In Salah gas field, about 1,200 km south of the capital, Algiers. Although it caused no casualties and no damage, it forced the facility to be closed as a precaution.

BP said that the temporary relocation was “a precautionary measure” and that they would continue to work with its joint venture partners remotely. Statoil informed that it will also temporarily remove its employees from the two sites in the coming weeks, as well as close its temporary operations center in Hassi Messaoud, a spokesman told AFP. Neither BP nor Statoil specified how many employees were impacted.

The rocket attack was the most serious since three years ago, when Al-Qaeda in the Islamic Maghreb (AQIM) assaulted another the gas facility at In Amenas, not far from the Libyan border, run in a joint venture. Forty people were killed during a four-day siege, and damages were so heavy that one processing plant remains out of operation, The New York Times reported.