DHAKA, Bangladesh—Bangladesh’s High Court on Monday rejected a petition brought by secular activists challenging Islam’s status as the country’s official religion.

The petition had threatened to inflame political tensions over the role of Islam in the Muslim-majority country.

Bangladesh’s first constitution, framed after independence in 1971, adopted secularism as one of its main principles, along with socialism. A constitutional amendment in 1988 declared Islam the state religion.

Lawyers for the petitioners, a group of 15 activists, had argued that recognizing Islam as the official religion contradicted the secular nature of the state.

The petition was filed in 1988 and the High Court’s case backlog meant it wasn’t heard until Monday. Most of the 15 plaintiffs who filed the writ—a diverse group of writers, academics and lawyers—are now dead.