Five masked men on Tuesday stormed into a 500-year-old shrine to a female Muslim saint near the capital Tunis that had previously been threatened by religious conservatives and set it on fire, the Interior Ministry said.

Hardline Islamists are suspected in the attack on the shrine of Sayyeda Aicha Manoubia, a 13th century holy woman. It was one of several recent assaults on mausoleums for local saints.

The attacks come as secularists increasingly worry that Tunisia's moderate Islamist ruling party is not confronting the extremist elements that have grown more active since the country's longtime dictator was ousted last year.

For centuries, local women have visited the tomb of the saint to ask for help with problems or to cure diseases, and many poor women seek sanctuary there.

The ministry quoted four women staying overnight at the shrine who said the attackers used flammable liquid to quicken the blaze and stole valuables from them.

Hardline Muslims known as Salafis oppose the veneration of saints, a long-standing North African tradition, saying it undermines the Islamic belief in monotheism. Salafis in Mali, Somalia and neighboring Libya have all targeted the tombs of saints.

In March, religious conservatives picketed outside of the shrine to Sayyeda Manoubia and distributed pamphlets condemning this "blasphemous" practice of venerating saints.

Human Rights Watch on Monday issued a report urging Tunisia's government to investigate attacks by religious conservatives against activists, filmmakers, artists and others they disagree with.