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Militants in northern Mozambique attacked a security convoy attempting to rescue more than 180 people who’d been under siege in a hotel near the $20 billion liquefied natural gas project that Total SE is building, according to three people familiar with the matter.

More than a dozen vehicles were ambushed late Friday during an operation to evacuate people from the Amarula Palma Hotel, and only seven vehicles managed to escape, two of the people said. While about 100 fled to the beach, many are feared dead, according to one person. The militants, who’ve previously aligned with the Islamic State, were still active in the town of Palma on Saturday morning, they said.

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The latest attack began on March 24, the same day Total announced it would resume onshore works at its project, after fighting in late December prompted the company to evacuate staff. Total, whose project is the biggest private investment currently in Africa, said it would issue a statement and is yet to do so.

The ongoing raid in Palma, less that 8 kilometers (5 miles) from Total’s camp and where a number of subcontractor companies are based, could be a watershed moment in the insurgency that threatens to dampen further foreign investment in the region. The rebellion that started in 2017 has left more than 2,600 people dead and caused about 700,000 more to flee their homes.

Human Rights Watch said there were bodies on the streets in Palma, with residents fleeing after the assailants fired indiscriminately.

Omar Saranga, the Ministry of Defense spokesman, declined to comment by phone, saying the government would issue a statement.