While the coalition-backed Syrian Democratic Forces (SDF) are pushing towards Tabqah, thousands of people are fleeing the city and its surrounding villages to areas controlled by the SDF north of the Tabqah dam.
Around 7,000 people, some with animals, have arrived in the SDF controlled areas since last week, according to a SDF statement on Friday.
Video footage and images of people on vehicles and on foot leaving areas controlled by the Islamic State circulated on social media.
Tabqah is located 55km west of IS stronghold Raqqah, which has been encircled by the SDF ahead of a final operation to storm the city in April.
The UN Refugee Agency (UNHCR) has estimated that there are 6.5 million people, including 2.8 million children, displaced within Syria, which makes Syrians the biggest internally displaced population in the world.