"Iran... as always expresses its readiness to assist and cooperate with other countries to confront these criminals, who deal death and ignorantly spread hate," foreign ministry spokesman Bahram Ghassemi said.
Six foreign pilgrims were wounded when a suicide bomber blew himself up near the Grand Mosque in Mecca, where hundreds of thousands of worshippers had gathered for prayers on the last Friday of the Muslim fasting month of Ramadan.
The Saudi interior ministry said a wider plot had been foiled with the arrest of five suspects earlier in the day.
Shiite Iran and Sunni Saudi Arabia are locked in a bitter battle for regional influence and have had no diplomatic relations since January last year.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)