Opposition figure Kizza Besigye is also calling for the release of Bobi Wine from prison.
Earlier, presidential candidates Mugisha Muntu, Henry Tumukunde and John Katumba called off their campaigns in solidarity with detained colleagues.
FDC presidential candidate Patrick Amuriat who was detained in Gulu city has since been freed.
Only Bobi Wine is still detained at Nalufenya in Jinja city.
“•Free Hon Robert Kyagulanyi (Bobi Wine) NOW,” Besigye said on Thursday.
Free Ugandans NOW, he demanded carrying a poster inscribed on #FreeBobiWine.
He said Ugandans remain firm and take actions to end captivity NOW.
“International Criminal Court, please process petition of Ugandans; more heinous crimes underway.”
“Those funding the Rogue NRM/M7 Junta must stop. STOP ODIOUS DEBTS.”