In a statement, al-Shabab said it released "all the Muslim prisoners" from the facility.
The rare honour is reserved for electoral bodies that demonstrate exceptional integrity, professionalism
A group called Gen Z 212 has been coordinating the demonstrations through the gaming and streaming platform Discord, as well as TikTok and Instagram.
At least 22 people have been killed and more than 100 others injured in the unrest, according to the UN.
"Stadiums are here, but where are the hospitals?" is a popular chant among the Gen Z protesters.
Robert Mugabe Jr, 33, was arrested on Wednesday morning as he drove the wrong way down a one-way street.
The latest strike on Al-Zurq market has reignited calls for global intervention.
Dozens of civilians were killed and many others wounded in the attack.
Tanzania's government spokesperson Msigwa said the clip was misleading, urged the public to disregard it.
