The three were detained without charges in June.
RSF says it is "appalled by the attitude of the Turkmen authorities, who are flouting the basic rules of justice and human rights with impunity."
Khajiev is a relative of Tajigul Begmedova, the chairwoman of the Bulgaria-based Turkmen Helsinki Foundation rights group. He is reportedly due to appear before a court on August 25 on charges of illegal weapon possession.
RSF says the trials of Muradova and THF activist Amanklychev could begin by the end of the month.
LIFE UNDER NIYAZOV: On July 21, RFE/RL's Prague broadcasting center hosted a presentation by TAJIGUL BEGMEDOVA, chairwoman of the Bulgaria-based Turkmenistan Helsinki Foundation for Human Rights (THF). Begmedova discussed the human rights situation in Turkmenistan under President Saparmural Niyazov, focusing on the arrests in June of THF activists and RFE/RL Turkmen Service correspondent Ogulsapar Muradova. Begmedova, who graduated from the Institute of Economy in Moscow in 1987, fled Turkmenistan in 2002 and lives in exile in Sofia.
LISTENListen to the complete presentation (36 minutes; presentation in Russian with consecutive translation into English):
Real Audio Windows Media
Some RFE/RL Coverage Of Human Rights In Turkmenistan:
ARCHIVE RFE/RL coverage of Turkmenistan.