Most shops were shuttered Friday in the northern Morocco city of Al-Hoceima, the second day of a general strike called by activists demanding the release of a protest leader.
Nasser Zefzafi, who emerged as the head of the grassroots Al-Hirak al-Shaabi, or "Popular Movement", was arrested on Monday after three days on the run.
His arrest sparked protests in the neglected Rif region of northern Morocco, where demonstrators have been demanding more development and railing against corruption, repression and unemployment.
The port of Al-Hoceima in the Rif has been shaken by social unrest since the death last October of fishmonger Mouhcine Fikri, 31, who was crushed in a rubbish truck as he protested against the seizure of swordfish caught out of season.
Most shops in Al-Hoceima city centre stayed closed on Friday, except for two or three pharmacies and a supermarket.
Al-Hirak had called for a three-day strike until Saturday.
It also urged supporters to boycott mosques on Friday, the main day of worship, and to pray instead on the streets as a form of protest against sermons sanctioned by state.
Zefzafi was detained along with others on Monday for "attacking internal security", after a warrant for his arrest issued a week ago Friday sparked turmoil in Al-Hoceima, a city of 56,000 inhabitants.
He is also accused of having interrupted the sermon of an imam in the main mosque of the city, accusing him of inciting the congregation against the protest movement.
Correspondents said most mosques in Al-Hoceima were full for the weekly prayer, except for one near Zefzafi's house.
In the neighbouring town of Imzouren, residents worshipped on the street outside the mosque, according to footage posted online.
Zefzafi's arrest sparked angry but mostly peaceful protests for nearly a week, with thousands of people taking to the streets where security forces were heavily deployed.
Government spokesman Mustafa El-Khafli said authorities have detained around 40 people since last Friday, 31 of whom are still under arrest, the official MAP news agency reported.
Core members of Al-Hirak were among those arrested.
"The doors to dialogue remain open with civil society," El-Khalfi was quoted as saying by MAP.
He said 700 sit-ins have taken place over the past seven months in the Rif, including 150 in Al-Hoceima.