The detainees belong to the officially registered Birdamlik nongovernmental group and were planning to peacefully march through the town.
Talking to RFE/RL's Uzbek Service after she was released from police custody, Birdamlik member Oisha Mamanazarova said the authorities put the group under police surveillance as soon as they heard of the planned march.
"We wanted to celebrate this holiday among ourselves," she said. "For the past three days, the administration had tried to frighten us. Police cars were posted near the houses of our members -- even those who do not live in [Shahrisabz] district -- and they were forbidden to go out in the streets."
Mamanazarova also said her group had duly requested permission to march through the town. However, its request was left unanswered.
In the request, posted on its website, Birdamlik pledged not to raise "any political, economic, or social demands" during the march.
In related news, the Tashkent-based Initiative Group of Independent Human Rights Defenders says in a statement that all civic campaigners living in the Uzbek capital have been under effective house arrest for the past two days.
The group says that, like in Shahrisabz, all rights activists are under strict police surveillance and barred from leaving their homes.
(with birdamlik.info, ingpu.com)