Story highlights Explosion comes day before President Duterte visits Marawi

Philippines army currently fighting militants in the region

(CNN) Nine members of Philippines President Rodrigo Duterte's security team have been injured after their convoy was hit by an explosive device.

One person is in a critical condition after the blast in Marawi, in the southern island of Mindanao. President Duterte was not with the convoy.

"We assure our brave men and women who put their lives on the line for duty and country that their Commander-in-Chief will never abandon them in their time of need," Duterte's spokesman Martin Andanar told CNN.

Bomb disposal officers inspect an improvised explosive device in Manila on November 28.

Militant attacks

The team were part of a 50-person advance convoy preparing for Duterte's planned visit to Marawi on Wednesday, Colonel Gene Ponio told CNN Philippines.