Militants occupied a vital port in gas-rich northern Mozambique on Wednesday following days of attacks claimed by an ISIS-affiliated group, a military source and local media said. It is the third time militants have seized the port, a logistics link for a $23 billion (Dh84bn) natural-gas project being developed by French energy firm Total. "The port of Mocimboa da Praia was captured by the terrorists at dawn," the Moz24Horas website reported, while a military source told AFP that the small town and its port had "fallen". The assault is the latest in an intensifying insurgency in the country's north since 2017 that has killed more than 1,000 people and complicated plans to develop offshore gas reserves. Mozambique's defence forces (FDS) confirmed that "terrorists" had launched "sequenced attacks" on several villages surrounding the port over the past week in an attempt to occupy the town. "At the moment, there are ongoing actions to neutralise the terrorists that are using populations in the affected areas as shields," the FDS said in a statement. Mocimboa da Praia lies less than 80 kilometres south of the Afungi peninsula where a liquefied natural gas (LNG) facility, one of Africa's biggest single investment projects, is located. The port is the closest harbour and a gateway for materials and supplies to the gas project where Total is in the preparation stage having recently finalised an initial $15bn of financing. “The capture of Mocimboa da Praia, as well as the previous assaults on district capitals since March, shows that the capabilities of ISIS militants has improved,” Tristan Gueret, an analyst at Risk Advisory Group in London, said. Gas projects in the country’s northern Cabo Delgado province are central to plans to transform the impoverished south-east African nation. Projected revenue from the developments are estimated at more than three times its current gross domestic product. “Although it is another indication of the fast deterioration in the security environment in Cabo Delgado, the success of the attack in Mocimboa da Praia does not necessarily have major or immediate implications for LNG operations,” Mr Gueret said. The Total project area is “currently secured by a dedicated force, and this means that mounting a successful raid there would be much more challenging for the group,” he said. The military source said that during Wednesday's assault a rocket-propelled grenade sank a boat owned by former president Armando Guebuza. "The situation is complicated," the source said. Under Mr Guebuza, Mozambique secretly borrowed about $2 billion (Dh7.3bn) from Credit Suisse and Russia's VTB Bank to finance maritime surveillance and buy military and tuna fishing vessels from Privinvest in 2013 and 2014. But the government only disclosed the debt in 2016 – a development that plunged the poor, donor-dependent southern African country into its worst-ever financial crisis. Attacks in the northern region have already killed at least 1,300 people, according to the Armed Conflict Location & Event Data Project (ACLED). Displaced people number more than 250,000, according to aid organisations working locally. In its latest weekly report released on Wednesday, ACLED said "insurgents and government security forces have been in more or less constant running battles in the area" for the past week. Even with the help of private military contractors flying helicopters armed with machine guns, the Mozambican government has struggled to curb the insurgency, which has grown increasingly brazen in its attacks this year. Security forces have in the past seven days killed 59 fighters in the region and destroyed six of their camps, the government said. Fighting is continuing in order to “neutralise” the militants, it said. The attacks started in 2017 in Mocimboa da Praia and have since spread to massive territories of Cabo Delgado province. The latest attack – the third on the town this year – was claimed by ISIS Central Africa Province. The ISIS-affiliated group has the stated goal of establishing a so-called “caliphate” in the region. The ISIS branch has claimed several attacks since June 2019 through social media, often posting images of slain soldiers and seized weapons.