The much-touted demonstrations planned for Thursday, during the celebrations to mark 54 years of the union between Tanganyika and Zanzibar, aborted as armed police officers patrolled the streets of major towns.
Dar es Salaam Special Zone Police Commander Lazaro Mambosasa told reporters on Thursday that nine people were arrested in connection with the planned anti-government demonstrations. Mr Mambosasa said the nine were arrested in Dar es Salaam with anti-Magufuli placards.
The EastAfrican did not see any marchers anywhere.
In the northern town of Arusha, an opposition stronghold, police on Tuesday arrested seven people accused of mobilising the public to take part in the planned demo.
For the past three months, government critics have been planning demonstrations through social media to push for more freedoms, and to protest what they say is kidnapping and killing of government critics.
President Magufuli and the police declared the planned protests illegal and cautioned the public against taking part in them, warning of stern action against the marchers.
At least a dozen of people have been arrested in the past three weeks in connection with mobilising the public for the demonstrations.
Demonstrations are allowed in Tanzanian laws. Section 44 of Police Force and Auxiliary Services Act require a person to notify the police of the intension to convene or assemble. The police may allow it or issue a stop order if they believe the assembly may constitute breach of the peace.
The call for the countrywide demonstrations was championed on social media by Mange Kimambi, a Tanzanian living in Los Angeles, US.
Ms Kimambi, who has about 1.8 million followers on Instagram, was an ardent supporter of Dr Magufuli during his campaign for the presidency in 2015. But she seems to have had a change of heart a few months after Dr Magufuli, nicknamed Bulldozer, took office.
Meanwhile, Tanzanians in Sweden and Washington DC, US, held their protests on Wednesday.
Tanzania’s ambassador to Sweden Dr Wilbrod Slaa told a local newspaper that about 10 people arrived at the embassy wielding placards but declined his invitation into Tanzania House to lodge their concerns.