Japanese companies are withdrawing their employees from Algeria following the bloody four-day hostage crisis at a natural gas complex with the death toll still expected to climb.

Firms such as JSM Ltd. and IHI Corp. have asked their representatives in the capital city of Algiers to immediately leave the country and instructed local workers to temporarily refrain from traveling long distances to desert and mountainous areas, where they could be at risk of becoming the target of militants, reports the Asahi Shimbun.

An official from JSM Ltd. said Algiers is far from the remote In Amenas gas plant in the Sahara but expressed fear that a civil war may break out. Travel agencies have also cancelled tours to Algeria.

Death tolls climbed to at least 81 when Algerian forces searching the gas facility found 25 more bodies after storming the complex last week which resulted in a bloody assault that killed around 30 captives and 11 militants. The number of confirmed fatalities was likely to rise, a security official who spoke on condition of anonymity said, adding that many were badly disfigured that they could not immediately be identified.

A source from the In Amenas hospital said twelve bodies being held at the morgue were Japanese, AFP reports. Japanese engineering firm JGC told AFP that 10 of Japanese workers and seven of its foreign workers remained unaccounted for.

A total of 685 Algerian and 107 foreign workers were freed over the course of the four-day siege, while the fate of many foreign nationals are still unclear, AP reports.

The militants reportedly wanted a prisoner swap with authorities. “We want the prisoners you have, the comrades who were arrested and imprisoned 15 years ago. We want 100 of them,” Abdel Rahman al-Nigri, the leader of the hostage takers said in an audio recording of his conversation with Algerian security forces.