Tanzanian police banned all opposition protests till further notice on Tuesday after security forces used tear gas to disperse a crowd rallying against "undemocratic actions" by President John Magufuli's government.
Tanzania's main opposition parties have called for nationwide rallies to protest against the government's decision to ban live televised parliamentary debates.
The parties have described that move, along with the suspension of seven opposition lawmakers from parliament, as undemocratic.
George Kyando, a police official, told Reuters they had been forced to use teargas to break up the crowd "after we received intelligence reports suggesting that there was a likelihood of an outbreak of violence".
In a statement police also said they had received intelligence reports that the opposition planned to use the public rallies to call for the launch of a campaign of civil disorder in the east African country.
The leader of one opposition party said on Twitter the reasons given by the police for banning the rallies were baseless.
"When we air our views in parliament we are thrown out. Outside parliament, our rallies are banned," Zitto Kabwe, leader of the opposition ACT Wazalendo party, tweeted.
The leader of the main opposition CHADEMA party, Freeman Mbowe, accused the government of excessive use of force in breaking up the opposition rally.