After days of heavy fighting in northern Mozimbique, there are reports that rebels, linked to the so-called Islamic State group, have captured a key port.

According to multiple sources, the city of Mocimboa da Praia was seized by Islamist fighters on Tuesday, forcing government troops to flee.

This is a heavy blow for Mozambique’s security forces.

Low on ammunition, and facing a large, well-coordinated rebel attack, government troops are reported to have abandoned the port city of Mocimboa da Praia, with many soldiers fleeing by boat.

The question now is whether the rebels will – as they’ve hinted – try to hold onto this strategic city.

That would mark a new escalation in a shadowy conflict that represents a major threat to Mozambique and to international plans to develop vast off-shore gas fields.

The rebels have formal ties to IS, but are also feeding on local grievances in a long-neglected corner of the country.

Mozambique’s neighbours are watching with growing anxiety.

A private security contractor based in South Africa is supplying helicopter support to the army.

But this latest attack appears to show the rebellion is still gaining in strength and sophistication.