Police in Uganda announced the arrests of opposition activists this week amid speculation that longtime President Yoweri Museveni is planning to change the constitution so he can stand for re-election.
No official move has been made to lift the bar on Museveni running due to his age, but Ingrid Turinawe, senior organiser for the main opposition Forum for Democratic Change, said he believes the arrests of 56 party members on Wednesday were linked to the speculation.
"The government gets suspicious that whoever is meeting is discussing the age limit. These activists weren't discussing the age limit, but even if it was true what's wrong with that?" Turinawe told AFP.
Currently, the constitution prohibits citizens over the age of 75 from running for president.
Museveni -- who has ruled the east African nation for 31 years -- will be 77 when elections are next due to be held in 2021.
Separately, police spokesman Emilian Kayima said the leader of a smaller opposition party and 13 members were arrested on Thursday for illegal assembly.
Local media reported those detentions came after the party members were found collecting signatures for a petition opposing the rumoured constitutional change.
For weeks, Ugandan media has speculated that moves are afoot to amend the age limit in Uganda's charter so that Museveni can run for office again.
On Wednesday, the president publicly acknowledged the constitutional rumours for the first time when he urged journalists at a press conference not to "waste your time" on the issue.
"I have heard about that talk going around but I have not bothered to ask," said Museveni.