Islamist insurgents took over most of the Mozambique town of Palma on Saturday, after slaughtering civilians as they tried to flee and trapping about 200 people inside a hotel. Details on the fate of those trapped—many of whom are said to be foreign workers employed by international gas companies—were scarce, as communication lines in the town have all but been cut off. Dozens of those trapped reportedly managed to escape on Friday, and another 20 were said to have been rescued by helicopter on Saturday morning. But by Saturday night, hundreds of insurgents had surrounded four hotels known to be popular with foreign workers involved in work on liquefied natural gas projects in the area, according to The New York Times. The siege of the town first began on Wednesday, when about 100 insurgents entered the area. By Saturday, the group—thought to be tied to the so-called Islamic State—had nearly tripled and managed to take over government buildings and cut off roads through which the government could send help. Thousands of people have fled the town amid the violence, but many of those who attempted to escape were reportedly killed in the streets. Witnesses quoted by CNN on Saturday described seeing corpses in the roads. “Armed groups’ horrific abuses pose a threat to civilians throughout the region,” said Dewa Mavhinga, southern Africa director at Human Rights Watch.