Iraqi forces say they have secured the southern edge of the Islamic State group stronghold of Fallujah, two weeks after the launch of an operation to recapture the city.

Lieutenant General Abdel Wahab al-Saadi says his forces secured the largely agricultural southern neighbourhood of Naymiyah, under cover of US-led coalition air strikes, and are poised to enter the main city.

The slow-moving operation was announced in May. On Monday, Iraq's elite special forces began pushing into the city centre, but they have faced stiff resistance as Fallujah has been under Islamic State control for more than two years, and the militants have been able to erect complex defences.

Fallujah is one of the last strongholds of IS in Iraq. The militants also hold its second largest city, Mosul.

While Iraqi and Islamic State forces battle to take control of the city, an estimated 50,000 civilians remain trapped inside. 

The Norway Refugee Countil said that 2980 families have managed to make it to displacement camps. It said that fleeing families have been targeted by armed opposition groups, with an unidentified number shot and killed while crossing a river. 

NRC country director Nasr Muflahi said "our biggest fears are now tragically confirmed with civilians being directly targeted while trying to flee to safety. This is the worst that we feared would happen to innocent men, women and children who have had to leave everything behind in order to save their lives. We remain extremely concerned for the 50,000 civilians still trapped inside Fallujah.”