President Filipe Nyusi said the country’s army is battling ISIL-linked groups in gas-rich Cabo Delgado’s Macomia.

The town is in Cabo Delgado, a gas-rich northern province where groups linked to the ISIL (ISIS) group, launched an armed uprising in 2017. Despite a large security response, there has been a surge in attacks since January this year.

Two security sources told the Reuters news agency that hundreds of fighters are believed to be involved in the latest attack that took place on Friday morning.

“Macomia is under attack since this morning. Fire exchange still continues,” Nyusi said at about 10:00 GMT, adding that the armed group fighters initially withdrew after about 45 minutes of fighting, but then regrouped and came back.

Friday’s attack appeared to be the most serious attack in the area in some time.

A regional force from the Southern African Development Community (SADC), which deployed in Mozambique in 2021, started withdrawing last month as its mandate ends in July.

Piers Pigou, head of the Southern Africa Programme at the Institute for Security Studies, said the attack on the Macomia district headquarters validates concerns over a security vacuum opening up with the drawdown of the Southern African troops.

“Claims that the province has been for the most part stabilised are evidently not accurate,” he told Reuters.

Nyusi said that attacks can take place in such periods of transition and that he hoped the SADC forces would be able to step in and help. It was unclear if they were still deployed in the area or involved in the fight.

Rwanda has also deployed troops to Mozambique to help fight the armed groups.

Figures released by the International Organisation for Migration in March show more than 110,000 people have been displaced since the end of last year, amid escalating violence in the province.

The offensive comes as French oil company TotalEnergies is seeking to restart a $20bn liquefied natural gas terminal in Cabo Delgado that was halted in 2021 due to the violence. That project is some 200km (124 miles) north of Macomia, the town under attack.

ExxonMobil, with partner Eni, is also developing an LNG project in northern Mozambique and said last week that it was “optimistic and pushing forward” as the security situation had improved.