Abderrahman said the radicals tried to advance from the municipal building in central Kobane, a mostly-Kurdish town located on the border with Turkey.
He also confirmed that US planes had dropped large supplies of weapons and medical gear to the Kurdish forces.
Abderrahman said the operation took place overnight and that the supply drop could change the balance of power on the ground.
The Kurdish militants have been fighting with medium and light weapons against the jihadis who possess heavy weapons and tanks since the IS launched its attack on Kobane last month.
The extremists are besieging Kobane from all sides except the north that borders on Turkey which is preventing Kurds from crossing into Syria to join the fight.
US-led coalition aircraft have so far launched 135 air raids against IS positions, resulting in the deaths of hundreds of radicals as well as material damage, the US Central Command said in a statement.
The last raid launched by the warplanes occurred early Monday in the west of the Kurdish town, according to SOHR.
Over the past several days, the IS has managed to seize more than one third of Kobane, sources said.