More than 180 people including expatriate workers have reportedly escaped from hotel in a northern Mozambique town, which was besieged by insurgents for three days, workers and security sources said on Friday.

Several people were reportedly killed during the escape bid, according to witnesses and a rights group, after the attack in Palma near a liquified natural gas site in Cabo Delgado province.

French oil giant Total is the principal investor in the $20 billion project — Africa’s largest — with six other international firms including ExxonMobil involved in the area.

Extremist militants began a raid on the coastal town on Wednesday afternoon, forcing terrified residents to flee into surrounding forest as LNG and government workers sought shelter at the Amarula Palma hotel.

“Almost the entire town was destroyed. Many people are dead,” said a worker on the LNG site speaking on the phone Friday evening after he was evacuated to Afungi.

Jasmine Opperman, a security analyst who specialises in the terrorist threat in Africa said that the attack on the town and the hotel had been “meticulously planned.”

As locals fled to the bush, workers from LNG companies, including foreigners, took refuge in hotel Amarula where they are waiting to be rescued,” said a security source, asking not to be named.

Human Rights Watch said the attackers are linked to a group known locally as Al Shabab, which has no known direct link to the Somalian terrorist organisation with a similar name.

Several witnesses told Human Rights Watch that they saw bodies on the streets and residents fleeing after the Al Shabab fighters fired indiscriminately at people and buildings,” the rights group said in a statement on Friday.

South African news website News24 reported that one South African national had died during the attack.

Another worker from a company subcontracted by Total said helicopters flew over the hotel earlier on Friday trying to find “a corridor to rescue the approximately 180 people trapped in the hotel”.

According to the South African news outlet Daily Maverick, the helicopters were being flown by Dyck Advisory Group, a controversial South African private security firm working with the government of Mozambique.

“Until nightfall many people remained on the premises while militants tried to advance towards the hotel,” he said.

In an unverified short video clip shared on social media, an unidentified man filmed the hotel lobby showing several people milling around the patio.

The buzzing sound of a helicopter in the background, he described the situation in Palma as “critical”.

“We don’t know if we will be rescued,” he said, adding the hotel had run out of food but still had water