Lanao Del Sur (CNN Philippines) — Seven members of the Presidential Security Group (PSG) and two military troops were wounded, after they were hit in the blast of a suspected improvised explosive device (IED) in Marawi City, Lanao Del Sur on Tuesday.

Aside from the explosion, the attackers also opened fire on the soldiers.

Among these victims, one PSG member and one soldier are critically injured.

The military's Western Mindanao Command (WESMINCOM) Spokesperson Major Filemon Tan confirmed this information.

Col. Gene Ponio, deputy brigade commander of the 103rd Brigade, said the personnel were part of a convoy of the President's advance party in Marawi.

At least 50 people were part of the convoy, including personnel from Presidential Broadcast Staff Radio-Television Malacañang (RTVM) and military escorts, Ponio said.

Ponio said the incident may be a diversionary tactic by the Maute group, an Islamist terrorist group in Mindanao. The Maute group is facing an intense military offensive after it laid siege to Butig town in Lanao Del Sur last week.

The advance party was preparing for the scheduled visit of President Rodrigo Duterte in the province on Wednesday.

The two critically injured victims were airlifted to the Fourth Infantry Division headquarters in Cagayan De Oro City, while three others were transferred to a hospital.

President Duterte will proceed with visit to Marawi City on Wednesday despite the blast, adding he will take the same route as the convoy.

"'Yung advance party ko belonging to PSG, na-ambush pa kanina, natamaan kanina. I am going there," Duterte said on Tuesday afternoon.