There have been fears about the integrity of the dam after fighting in the area forced it out of service yesterday, following earlier UN warnings that a collapse would be "catastrophic".
With air support from the US-led coalition against IS, the Syrian Democratic Forces are fighting to seize the town of Tabqa and the adjacent dam on the Euphrates River, as part of their battle for the jihadists' stronghold in nearby Raqa.
"This is to allow a team of engineers to enter the dam and carry out their work."
Ahmed said the pause could be extended if necessary.
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The IS-held structure was forced out of service yesterday after its power station was damaged, a source there told AFP.
The United Nations has warned that damage to the dam "could lead to massive scale flooding across Raqa and as far away as Deir Ezzor" province downstream to the southeast with "catastrophic humanitarian implications".
"If fixing the damage will require more time, then we will coordinate with the SDF to request additional time to finish repairs, resume the dam's work and remove any threat to it," the source added.
IS issued warnings through its propaganda agency Amaq yesterday that the dam could collapse "at any moment".
The US-led coalition said today it was "taking every precaution" to ensure the structure's integrity.
The SDF had also denied the dam was damaged, and said military operations around it were being conducted "slowly and with precision".
The alliance of Kurdish and Arab fighters launched its offensive for Raqa city in November, seizing around two thirds of the surrounding province, according to the Britain-based Syrian Observatory for Human Rights.
At their closest point, they are just eight kilometres from the city, to the northeast.
But they are mostly further away, between 18 and 29 kilometres from Raqa.