More than 40 women, four of whom had babies with them, were reported released Saturday in Zimbabwe's second city, Bulawayo, after spending two days in police cells. The women had been protesting against security laws that were introduced before last year's disputed presidential election.
The jailed women were part of a group who demonstrated against the Public Order and Security Act.
Legal analysts say this clutch of security laws is even tougher than those they replaced, which were brought into force during the colonial era.
After independence from Britain in 1980, President Robert Mugabe never abolished the Law and Order Maintenance Act, under which he himself had once been detained.
When the colonial law was thrown out last year, it was immediately replaced by new security legislation designed by Justice Minister Patrick Chinamasa.
Mr. Chinamasa has emerged from within the ruling Zanu PF party as Mr. Mugabe's front man to establish peace talks with the opposition Movement for Democratic Change.
Opposition groups say there can be no political solution to Zimbabwe's political crisis while this legislation remains on the statute books.
Thousands of people have been arrested since the legislation was passed into law shortly before violence-marred presidential elections in March 2002. Human rights groups claim that more than 95 percent of those arrested were supporters of opposition groups.
One section of the law makes it an offense for more than three people to hold a public meeting, without prior permission from the police.