MANILA - Malacañang on Friday fended off criticism that the campaign against terror took a backseat under President Rodrigo Duterte because of his focus on the war on drugs.

In a news conference in Duterte’s native Davao City, Presidential Spokesperson Ernesto Abella said the President recognized the terror threat just over a month after taking office.

Attacks of Islamic State-linked terror groups in Marawi City has emerged as Duterte's biggest challenge a year into his presidency, with the conflict still raging more than a month since it erupted.

“Let me remind you that as early as August last year, one and a half month after [Duterte] assumed presidency, the President already told the Philippine military to be ready with ISIS (Islamic State in Iraq and Syria) and warned that the country would be plagued with the ISIS disease,” Abella said.

• Read: Duterte: ISIS a looming problem for PH

“He was pointing it out as of last year that there was indeed a looming danger, except at that particular stage, it was at the stage of indoctrination.”

Critics and analysts have said Duterte seemed to have overlooked the buildup of Islamist militants in Mindanao, the President’s home island, as he poured most of the government’s time and resources on combating the illegal drug menace.

ISIS sympathizers, led by the Maute and Abu Sayyaf groups, on May 23 laid siege to Marawi City, an economic and cultural hub in Muslim Mindanao.

The siege has triggered a humanitarian crisis, with more than 400,000 residents displaced from Lanao del Sur's capital and outlying areas.

At least 429 people - 303 suspected terrorists, 44 civilians, and 82 government troops - have died since the clashes erupted.

Marawi, the most important Muslim city in the mainly Catholic Philippines, has also been left in ruins after 38 days of fighting.

While government has put the civilian death toll at 44, the military believes this could “increase significantly” as troops have yet to reach other parts of the city where some trapped civilians are feared to have been executed.

The clashes had prompted Duterte to place the entire Mindanao under martial law, citing the militants’ bid to establish an Islamic State province in Mindanao. Government, nonetheless, insists there was no failure of intelligence that led to the crisis, saying the military was able to preempt a much larger attack.

The rise of pro-ISIS groups in the country has also raised alarm in Washington and the Philippines’ neighbors in the region, which fear that the notorious terror group was seeking to establish a new front in Asia amid its successive losses in Iraq and Syria.

While the military has expressed confidence that the crisis will be over soon, security experts worry that the Marawi attack was just part of a bigger plan of Islamic State in Southeast Asia.