Islamic State (Isis) enforcers have reportedly told residents of its stronghold Raqqa that they cannot flee the city after a militia coalition dropped leaflets on the city, urging citizens to leave. The Daesh (Isis) stronghold was littered with leaflets dropped from high above the city saying, "The time you have been waiting for has come, the time to leave Raqqa."

According to the activist group Raqqa is Being Slaughtered Silently (RBSS) the leaflets were dropped twice this week, most recently on 20 May, and show three men, a woman and a child escaping a gloomy urban area in ruins heading to a peaceful green landscape.

The Pentagon says that the leaflets, part of a propaganda effort by the coalition, are not a precursor for an imminent Western-led attack on the city. But last week, a British fighter aligned with the Peshmerga, Macer Gifford, said that Kurdish fighters were preparing to assault Raqqa with Western help.

In January, IS began confiscating passports to make it harder for people to travel and began forcing people in the city to register so the militants can keep tabs on the population. IS have even reportedly cancelled their own fighter's holidays and bussed fighters top the frontlines around the city as they prepare for a huge battle.

"Their [Islamic State] positions used to be clear, but since the beginning of the air campaign against them, they've started to resort to hiding among civilians," said Abu Mohammad, an activist with the RBSS to the Telegraph.

Talal Silo, a spokesman of the Syrian Democratic Forces (SDF) – an umbrella coalition consisting of Kurdish People's Protection Units (YPG) with Arab, Christian and Turkmen militias – said troops were gearing up for a "very difficult battle" for Raqqa. He added that they are preparing a "three-pronged attack" on the city.

Last month, IS militants were spotted covering the streets of Raqqa with sheets to protect themselves from drone strikes. RBSS posted images of sheets laid across the top of homes and shops in the city.

Isis militant Raqqa
An Isis jihadi celebrates after Raqqa was captured in 2014 Reuters