A belt of land mines and checkpoints has been laid on roads in and out the northern Syrian city to prevent escape.
All men have been ordered to wear the jihadis' garb of baggy pants and long shirts, making it difficult to distinguish militants from civilians.
Hundreds, if not thousands, of Syrians who fled other parts of the country now live in tents in the streets, vulnerable to warplanes or ground fighting. Enormous tarps have been stretched for blocks in the city center to hide the militants' movements from spy planes and satellites.
Leaflets dropped by coalition warplanes give confusing directions one suggests areas closer to the Euphrates River are safer, but then another warns that boats crossing the river will be struck.
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Mass panic erupted Sunday, when IS announced on mosque loudspeakers that US strikes had hit a dam to the west.
Residents were urged to flee imminent flooding, and thousands did. The militants allowed them into IS-controlled countryside nearby, as long as they left their possessions behind, according to an activist who is in touch with people inside the city.
"The people really don't know where to go," said the activist, saying residents were caught between airstrikes, land mines and IS fighters mingling among civilians.
To get a picture of Raqqa, The Associated Press talked to more than a dozen people with knowledge of the city, including residents who were still there or who had recently escaped, and activists with organizations that track events through contacts inside, as well as diplomats, the US military and aid groups.
Almost all spoke on condition they not be identified, fearing for their own lives or the lives of their contacts. Getting information is difficult.