As the Syrian Democratic Forces (SDF) close in on the town of Tabqa in Syria's al-Raqa province, the "Islamic State of Iraq and the Levant" (ISIL) is using civilians to stop their advance, local residents tell Diyaruna.
Some fear ISIL will open the floodgates of Tabqa dam on the Euphrates River, the country's largest, to defend the nearby city of al-Raqa.
This would devastate villages in the water's path, they said.
In recent weeks, the Arab-Kurd opposition alliance has moved to within four kilometres of the dam, recapturing the last village between them and the dam held by ISIL.
The dam is just 500 metres from the town of Tabqa.
"When the Wrath of the Euphrates campaign began, ISIL elements started clamping down on the town's residents and banned them from entering or leaving the town," said Tabqa shopkeeper Hamad al-Nafeh, using a pseudonym out of fear for his safety.
Residents must now obtain special permission from ISIL in order to enter al-Raqa city, he told Diyaruna.
"Attempts to flee the town have even grown fewer in number because of the mines the group has planted everywhere, and its snipers who shoot at anyone who wanders away from the residential areas," he said.
Residents trapped inside Tabqa
ISIL has ratcheted up its restrictions on residents "in an attempt to use them as human shields and stop the advance of the liberating forces", said Tabqa native Ibrahim al-Shammari, 25, who joined the SDF a few months ago.
"The SDF are now only a few kilometres away from Tabqa," he told Diyaruna.
They are approaching from the north, near Suwaydiya Kabira village, he said, "and have been communicating with civilians in the area to co-ordinate their escape to safe areas".
"ISIL set up many observation and monitoring posts along most thoroughfares leading to the town, whose obvious task is to prevent any escape from the town," al-Shammari said.
There have been many cases of unarmed residents being shot, he said.
The SDF has formed special teams to deal with civilian affairs when the liberating forces draw closer to the town, al-Shammari said.
"There is ongoing communication with several groups inside Tabqa to co-ordinate their stealthy escape and keep them safe from harm when the city is stormed, including the designation of hiding places," he said.
Many young men from Tabqa have joined the SDF in order to liberate their town from ISIL, he said.
ISIL has been carrying out several executions every week in retaliation against those who co-operate with the liberating forces, shopkeeper al-Nafeh said.
The group accuses its victims of "being spies for the infidels", he said, adding that most are young locals or captured SDF fighters who have openly rejected ISIL or provided information to the coalition or the SDF.
The goal is to "intimidate citizens and ensure they do not revolt", at a time when ISIL's anxiety is growing amid its mounting losses, he said.
ISIL threatens Tabqa dam
Meanwhile, Syrian farmers near the Euphrates River are terrified ISIL will open the floodgates to defend al-Raqa, devastating villages and farms in the process.
The water level of the Euphrates has shot up over the past month near al-Raqa, AFP reported in early March.
Residents of farming villages scattered along the river's eastern bank say they are afraid the group will destroy Tabqa dam to slow advancing anti-ISIL forces.
"If ISIL goes through with its threat of blowing up the Tabqa dam, then all areas around the southern part of the river could be under water," said local resident Abu Hussein, 67.
"A major disaster awaits the residents of Tabqa, al-Raqa and the areas around them, as everyone is living in fear of the dam collapsing," said Tabqa electrician Mohammed al-Kayyali, using a pseudonym out of fear for his safety.
ISIL has been manipulating the water discharge process, he told Diyaruna.
The group "has blocked the discharge of water to Aleppo to deprive citizens of water for drinking and irrigation, which has caused the water level in al-Assad lake to rise", he explained.
As SDF and regime forces drew closer to Tabqa, he added, "the group flooded the areas north of the lake to impede their advance, which eroded the agricultural areas, one of the few remaining resources in the region".
Al-Kayyali warned "of cracks that have begun to appear on the walls of the dam, which portends the imminent rupture and crumbling of the dam’s main abutments".
This could trigger the collapse of the dam and flood all villages, towns and agricultural areas around al-Assad lake, reaching as far as al-Raqa, he said.
Local residents also fear the group might intentionally destroy the dam if the area falls into the hands of the liberating forces, al-Kayyali said.
The strategic location of the dam means its capture would block all routes in and out of al-Raqa and hasten "the imminent fall of the city", he said.