Niyazov, an autocratic leader with a flourishing personality cult, says the 2002 plot to kill him was masterminded by the opposition in exile. Dozens of suspects were jailed.
Speaking on television late on Monday, Niyazov said he would pardon more than 10,000 prisoners in a mass amnesty, known as the "Night of All Forgiveness", later this week.
"Among them there are those who were linked to the 2002 terrorist act," he said. "Eight people have confessed, they did not take up arms..."
"All the others should stay (in jail), their guilt is huge, it's impossible to let everyone go."
Niyazov did not identify the eight.
The ritual is a much-publicised event in Turkmenistan, a mainly Muslim desert nation of six million where Niyazov, in power since 1985, is officially titled Turkmenbashi (Father of the Turkmen).
This year's mass release is scheduled for the night of Oct. 19, the last day of the holy Muslim month of Ramazan.

Copyright Reuters, 2006