At least 34 Iraqi security forces were killed in the border town of Al Qaim Friday, according to Agence France Presse.
The fighting began late Thursday near the Syria-Iraq border crossing, and did not end until around noon Friday, security officials told AFP. Militants are now primarily in control of the town, but it is not yet clear the identity of the militants.
Earlier this week, Syrian rebel groups took over control of the border crossing. Baghdad is now only in control of one out of three crossings.
Witnesses to the fighting told AFP that families are now fleeing Al Qaim en masse.
More than one million individuals have been affected by the increased violence in Iraq over recent weeks as the jihadist-linked ISIS expands its control within the country.