ISIS has almost doubled the land it controls in Syria since the US-led coalition began airstrikes against the extremist group in the summer, a new map has revealed.

The extremist group has continued to expand its 'caliphate', despite more than 800 airstrikes hitting targets in ISIS-controlled areas since last summer.

The map, created by the Coalition for a Democratic Syria (CDS), shows just how much land has fallen to ISIS - which now has a third of the country under its control.

Before the summer, the militants controlled just half that.

Scroll down for video

The map, created by the Coalition for a Democratic Syria, shows how much land ISIS have gained since August when the airstrikes bagen

It is thought a million more Syrians came under their control in the first two months of the bombing campaign, which saw the US-led coalition conduct more than 800 airstrikes in towns like Kobane (pictured)

When ISIS takes control of an area, it enforces strict Sharia law - which means executions and amputations for crimes are common

'Assessing the map, ISIS has almost doubled its territorial control in Syria. But more importantly, the number of people who now live under ISIS control has also increased substantially,' CDS political adviser Mouaz Moustafa told The Daily Beast.

It is thought a million more Syrians came under ISIS's terrifying regime within the first two months of the bombing campaign.

But the US and coalition forces have had an 'Iraq first' policy, and have focused their efforts on reducing ISIS's control there.

In addition to airstrikes, the US backs forces on the ground - although it does not have any of its soldiers fighting on the ground against the militants.

"We very much see ISIL [ISIS] largely in a defensive posture inside Iraq, that whatever momentum they had been enjoying has been halted, has been blunted.

'That has stayed steady over the last couple of weeks,' said Pentagon spokesman Rear Admiral John Kirby at a press conference on Tuesday, January 6, CNN reported.

But the US has said the airstrikes have worked to halt the spread of ISIS in Iraq

The US-led forces have an 'Iraq first' policy, which means focusing on ISIS territory in the north and west of the country

It has provided backing for Iraqi troops, seen here training to retake the northern city of Mosul

But a spokesman for the government admitted the area ISIS controlled in Syria had remained the same.

However, the coalition forces are continuing with regular airstrikes in both countries.

Yesterday alone, they conducted six airstrikes near Kobani, in Syria, while an airstrike near Ramadi, in Iraq, destroyed and ISIS barge and four of its boats.

Four more airstrikes were also carried out in Iraq, hitting buildings, mortar firing and fighting positions.

A released on the US Central Command's website explained the strikes 'further limits the terrorist group's ability to project terror and conduct operations'.