ISTANBUL

At least six Filipino soldiers were killed during an encounter with militants, believed to be behind last year's bombing at Mindanao State University, the Philippines army said on Monday.

Gen. Romeo Brawner Jr, the chief of the army, said the soldiers were killed in an operation against the “terrorist” Dawlah Islamiyah-Maute Group in the Munai area of northern Lanao Del Norte province in the southern Philippines’ Mindanao region.

Wounded soldiers have been evacuated for treatment, he added.

At least two militants were killed during the operation launched on Sunday, said the Filipino military general.

According to Georgi Engelbrecht, a senior analyst at Crisis Group on the Philippines, the operation has inflicted "one of the highest casualty figures" for the Filipino military "in the recent past."

At least four people were killed, and dozens of others injured, when a bomb hit a Catholic mass service at the university gymnasium. The attack was claimed by the Islamic State.

According to Gen. Brawner, at least 18 militants of the group have been neutralized in various operations, so far.