The Tajik government has accused the banned Islamic Renaissance Party of Tajikistan (IRPT) of being behind an attack that killed four foreign cyclists on July 29.
The Interior Ministry said in a statement on July 31 that the attackers were led by an "active member" of the IRPT, citing what it said was the confession of a detained suspect.
The ministry added that the group’s leader, identified as 33-year-old Hussein Abdusamadov, "underwent training in Iran."
The attackers planned to flee to Afghanistan after the incident, the statement also said.
Tajik authorities offered no immediate proof of the claims.
WATCH: Amateur Video Said To Show Attack On Foreign Cyclists In Tajikistan (WARNING: Disturbing Images)
At least four people suspected of involvement in the attack were killed by officers and five other suspects detained, Tajik police said.
On July 30, the Islamic State claimed responsibility for the killings. The extremist group's Amaq news agency published the claim without providing details or evidence to back up its statement.
Two Americans, one Dutchman, and a Swiss citizen were killed by at least one assailant with a gun and knife after being plowed down by a vehicle in the Danghara district of the Khatlon region, about 150 kilometers south of the Tajik capital, Dushanbe.
Three other foreigners -- including one Dutch, a Swiss citizen, and a French national -- were also injured in the attack.
The two Dutch victims were a couple identified by the country’s media as 56-year-old Rene Wokke and Kim Postma, 58.
Tajikistan banned the IRPT in 2015 as a “terrorist organization” and imprisoned dozens of its officials and members. Until then, the IRPT had been the only legal Islamist party in Central Asia.
The IRPT was first banned in 1993 but was legalized again in 1998 after the end of the Tajik civil war in the 1990s.
With reporting by Reuters and AFP