First Deputy Interior Minister Sharif Nazarov said the suspects have confessed to planning terror attacks in marketplaces and discos in the capital, Dushanbe.
Nazarov said ammunition, detonators, and explosives were seized during searches targeting members of the banned group.
He added that the Tajik authorities have information indicating that the Islamic Movement of Uzbekistan is also active in Afghanistan, while other members have been detained in Kyrgyzstan and Russia.
The IMU is regarded as a terrorist group by the United States and the Shanghai Cooperation Organization, of which Tajikistan is a member. Officials have pointed to leadership and training ties between the IMU and Al-Qaeda.
Twenty-three IMU members were reportedly detained in Tajikistan last year.
(with material from agency reports)