Dodoma - Tanzanian opposition Chadema party leader, Edward Lowassa has reportedly been arrested after police said he disobeyed a government order, All Africa reports.
Lowassa was arrested together with other officials from his party.
Police claimed that Lowassa contravened an order that prohibited any meetings that could entice people to join in the planned September 1 demonstration.
News24 reported recently that opposition parties and rights activists had criticised the move by police to ban political rallies "indefinitely", saying the development was a violation of freedom of speech.
According to The Monitor, a recent opposition rally in the Kahama District was met with tear gas, just a few hours after the ban was announced. This was seen by observers as blatant tactics by the government to silence any persons or organisations critical of the ruling party.
Reports indicated that Chadema was planning countrywide rallies on Thursday, to protest what the party believed were infringements on freedom of expression and democracy since Magufuli came into power.
According to BBC, Chadema confirmed a plan to hold a countrywide rally on Thursday.
Dar es Salaam Special Zone Police Commander, Simon Sirro confirmed that the men were arrested for contravening the nationwide ban on enticing rallies after being released later on bail.
The Chadema officials were now required to report back to the police on September 1 2016, the day of the planned rally.
Lowassa was the main challenger to incumbent President John Magufuli during last year's presidential elections.