In the last two weeks, at least 21 protesters have been killed.
Between 200 and 250 protesters were killed over this period.
This was the scene of the worst recent violence in which security forces killed at least 70 protesters.
On 3 April 1970 a protester was killed by the police.
Three protesters and a police officer were killed during the protests.
At least 846 protesters were killed during the 18-day revolt.
Soviet security forces are estimated to have killed at least 200 protesters on the square.
He was also serving there in 1990, when Soviet troops killed more than 100 protesters.
At least three protesters were killed in clashes with the police.
The uprising developed further with some protesters killed by British forces.