The reported thwarted attack led to 11 arrests and comes after a string of diversionary attacks by the jihadists since the start two weeks ago of a massive offensive against IS bastion Mosul.
Iraqi forces "arrested 11 Daesh (IS) members who were planning to attack the city" from the suburb of Al-Tash, on the southern edge of Ramadi, said Captain Ahmed al-Dulaimi of the Anbar police.
Iraqi forces retook Ramadi from IS early this year. Mine clearing and reconstruction efforts are under way but few civilians have returned.
The loss of Mosul could spell the end of IS's days as a land-holding force in Iraq but observers warn the group's remnants could increasingly activate sleeper cells to carry out spectacular attacks in cities.
On October 21, sleeper cells joined up with militants who infiltrated Kurdish-controlled Kirkuk, sparking deadly clashes with security forces that lasted three days.
Since the start of the offensive on Mosul, IS fighters have also launched attacks on Rutba, an outpost in western Anbar that government forces retook earlier this year, and in the northern Sinjar region.