Hundreds of ethnic Tamil women demanded information on Friday about relatives who have been missing since Sri Lanka's civil war, defying widespread military surveillance, threats and the possibility of arrest.
The protesters held a peaceful rally in the northern town of Mannar and issued a 10-point memorandum to the United Nations high commissioner for human rights.
The letter asked the commissioner to help obtain information about their relatives and determine who was responsible if they are dead. It also called for an independent international inquiry into allegations of war crimes during the civil war between government troops and defeated Tamil Tiger rebels, and the release of private land and homes occupied by the military.
The women say they have received no information about sons and husbands who surrendered to the military at the end of the fighting in 2009.
The protest came days after police arrested a mother and daughter who campaigned for the release of their kin.
Balendran Jeyakumari and her 13-year-old daughter were prominent in protests by relatives of the missing. Jeyakumari has a strong case against the government because of a photograph of her missing son in government custody. The photo appeared in a government publication, but authorities have refused to give her details about him or release him.
Jeyakumari was detained under the country's tough anti-terrorism law on charges that she harbored a former Tamil Tiger rebel. Her daughter has been handed over to probation officials.
Days later, two prominent human rights activists including a Catholic priest who tried to investigate what happened to Jeyakumari were arrested, sparking international criticism. They were released without charges but have been banned from traveling.
Rights defenders say the arrests are part of the government's efforts to intimidate its critics into silence. People who appeared to be secret police were seen photographing the protesters and writing down vehicle numbers on Friday.
Sri Lanka is facing a U.S.-sponsored resolution at the current session of the U.N. Human Rights Council over its failure to conduct an inquiry into alleged war abuses and human rights violations after the war.