A suicide bomber dressed in a traditional Muslim woman’s gown died after detonating a bomb outside a military camp in the restive southern Philippines, but no other casualties were reported, authorities said.

Suicide attacks were once very rare in the Philippines, but since July 2018 there have been four, including the latest explosion on Jolo island on Sunday.

The Islamic State claimed responsibility for all three previous suicide attacks, which experts have previously told AFP is a worrying escalation of extremism in the Philippines under the group’s influence.

According to a military statement, the attacker on Sunday was “foreign looking”, wore an abaya gown and appeared to be a woman. However, authorities had not confirmed the attacker’s gender.

No group has yet claimed the attack, which came a day after an IS-claimed bombing wounded eight at a market on the island of Mindanao.

Separatist groups in the Christian-majority nation’s south have waged decades-long insurgencies that have killed thousands.

This weekend’s attacks cast a shadow over a step toward a measure of peace in the region. The largest Muslim rebel group, the Moro Islamic Liberation Front, began to lay down its weapons on Saturday.

While the MILF has brokered peace with the government, other more extreme factions like jihadist group Abu Sayyaf continue to stage deadly attacks.