KUALA LUMPUR (Reuters) - A Malaysian activist who has campaigned for the rights of a sea-faring minority group was questioned by police under sedition laws on Thursday, a move that has exacerbated worries about backsliding on democratic freedoms under Prime Minister Anwar Ibrahim.

Mukmin Nantang, the founder of social advocacy group Borneo Komrad, was briefly detained by police as part of an investigation into the release of videos showing the destruction of Bajau Laut homes by authorities, his lawyer Nurul Rafeeqa said.

It was not clear if Mukmin will be charged, she added.

The Bajau Laut mostly reside in houseboats or rickety wooden huts built on stilts off the coast of Borneo island in Sabah state. Many don't have identification papers and are regarded by authorities as migrants.

Police in Semporna, a district in Sabah where many Bajau Laut homes were burnt down or demolished this month, did not immediately respond to a request for comment.

Authorities say the operation was carried out to boost security and combat cross-border crime.

Amnesty International Malaysia criticised the use of the sedition law against activists and urged authorities to end their investigation.

"The government has an obligation to protect human rights defenders, not arrest and attempt to intimidate. Furthermore, the use of the Sedition Act to silence the voices of human rights defenders is a clear violation of the right to freedom of expression," the group's executive director, Katrina Jorene Maliamauv, said in a statement.

Anwar, who spent nearly a decade in prison as opposition leader and campaigned on a progressive platform, has faced criticism over the slow pace of reform and the government's scrutiny of online content. The government has said this year it would review the Sedition Act, a move that has disappointed some rights groups which want the law to be abolished.

His government has also opened sedition and graft probes against opposition figures and increased scrutiny of the country's LGBTQ+ community. Corruption cases against political allies have also been dropped.

(Reporting by Rozanna Latiff; Editing by Edwina Gibbs)

By Rozanna Latiff