Many others have been reported wounded.
The Islamic Movement of Nigeria ( IMN) on Tuesday made good their threat as they marched on the streets of Abuja to observe Ashura procession.
Members of the movement converged on Wuse market as early as 7 a m and marched toward the popular Berger roundabout.
The protesters were seen waving flags with arabic inscriptions and chanting anti-government songs.
The protesters hurriedly dispersed on sighting armed policemen to avoid being arrested.
The protest caused gridlock in many parts of the city.
Kubwa and Mararaba expressways were completely locked down.
But reports from Kaduna State alleged that policemen have shot Shiite protesters, killing three people.
Many others have been reported wounded.
Also, reports have it that an unspecified number of protesters were shot dead by armed policemen in Gombe State.
SaharaReporters could not independently verify these claims.