Human rights experts from the United Nations on Friday expressed concern about the arrests of activists in the Bhima Koregaon case, and urged India to ensure that their cases are “promptly heard in line with international law”.

Ten activists have been arrested since June under the Unlawful Activities Prevention Act. Five of them are in prison, four under house arrest, and one has been released since.

The human rights experts said the vague definition of “unlawful activities” and “membership of terrorist organisations” in the law “confers discretionary powers upon state agencies, which weakens judicial oversight and diminishes civil liberties in the process”.

The Pune Police had arrested activists Shoma Sen, Surendra Gadling, Mahesh Raut, Rona Wilson and Sudhir Dhawale on June 6 as part of their investigation into violence during an event in Bhima Koregaon near Pune on January 1. On August 28, they arrested Sudha Bharadwaj, Gautam Navlakha, Vernon Gonsalves, Arun Ferreira and Varavara Rao.

On October 1, the Delhi High Court said Navlakha’s detention was untenable by law and ended his house arrest, but the Maharashtra government has now challenged it in the Supreme Court.

“We are concerned that terrorism charges brought in connection with the commemoration of Bhima-Koregaon are being used to silence human rights defenders who promote and protect the rights of India’s Dalit, indigenous, and tribal communities,” a statement by the UN experts said.

“We are very concerned about the charges against the human rights defenders and the continuing detention of nine of them,” the statement said. “All have been active in peacefully defending human rights, including those of marginalised and minority communities, political prisoners, and women, and their arrests appear to be directly related to their human rights work.”

The signatories of the statement were special rapporteurs and independent experts part of the Special Procedures of the Human Rights Council. They included Michel Forst, Fionnuala D Ní Aoláin, Fernand de Varennes, David Kaye and E Tendayi Achiume among several others.

“We appeal to the Indian authorities to ensure that due process, including the right to a fair trial, is provided to all detained human rights defenders, with a view to their prompt release,” the experts said. “We urge the government to refrain from engaging in the criminalisation of human rights defenders in general, including through the use of overly broad national security legislation.”

They added: “We wish to remind the Indian government of its obligation to protect and promote the rights of all human rights defenders, including women human rights defenders, as they peacefully carry out their legitimate work.”

On August 29, five citizens filed a petition before the Supreme Court seeking the release of Bharadwaj and the four other activists. The petition also sought an inquiry by a Special Investigation Team. But the top court rejected this plea on September 28 and gave the arrested activists time to seek remedy from a lower court.

The police claimed the activists were “urban Naxalites” who used an anti-caste commemoration event in Pune to whip up sentiments that resulted in the violence in Bhima Koregaon. This was part of a larger plot, the police claimed, to assassinate Prime Minister Narendra Modi and overthrow the government.