Kuwait authorities on Sunday released 20 stateless people arrested two days earlier during a protest that was forcefully dispersed by riot police, a judicial source said.
The release came as another group of the so-called bidoon went on trial in connection with similar protests earlier this year and were charged with illegal assembly with the intent to commit crimes.
The men who were freed had been arrested on Friday when hundreds of stateless people, known as bidoon, demonstrated in Jahra area northwest of Kuwait City demanding citizenship and other basic rights.
Two teenagers were among those freed after they were made to pledge that they will not take part in protests in the future, the source told AFP on condition of anonymity.
The 17 bidoons denied any wrongdoing at the start of their trial, during which they were also charged with assaulting security forces.
They are among a group of 52 stateless people facing trial on similar charges in Kuwait.
A first group of 31 stateleess people were charged last Monday with illegal assembly and assaulting police during demonstrations earlier this year to demand citizenship and other basic rights.
Mubarak al-Shemmari, one of several lawyers who volunteered to defend them, told AFP last week that the defendants face between three to five years in jail if the charges were proven.
He however described the whole case as "politically motivated" because no crime was committed and authorities could not provide any substantial evidence.
A trial for four others started on Wednesday.
All of the defendants are free on bail.
Under Kuwaiti law, only citizens have the right to hold public gatherings.
A number of Kuwaiti political groups and activists called for a gathering in Jahra on Monday in support of stateless people.
The interior ministry threatened that it will not allow such demonstrations to proceed anywhere in the kingdom.
Former MPs and political groups have warned the government against what they called "repressive" measures against bidoons and urged a peaceful and humanitarian solution to their problem.
Kuwait launched a crackdown on the estimated 100,000 bidoons in 2000, depriving them of health care, education and jobs.
The stateless claim they are Kuwaiti citizens who have been denied nationality. The Kuwaiti government meanwhile insists that a large number of them hold nationalities of other countries.
The wealthy Gulf state, which considers bidoons illegal residents, has said that it is studying the issue of the stateless carefully and is prepared to grant citizenship to those deemed deserving.