|Opposition lawmaker Hafiz Hussain Ahmed addresses an anti-American rally in Islamabad|
The demonstrations in Pakistan follow days of protests and riots in neighboring Afghanistan, where seven people have died this week.
Most religious leaders in Pakistan are urging their followers to keep Friday's protests peaceful.
The disorders in Afghanistan began on Tuesday, after the U.S. magazine Newsweek reported that American interrogators in Cuba deliberately destroyed a copy of the Koran, to intimidate a suspected terrorist.
The Pentagon says it cannot find any evidence that desecration of the holy book ever took place.
As a conservative Muslim nation, Pakistan views insults to the Koran as blasphemy punishable by death.
Some information for this report provided by AP and Reuters.