MARAWI, Philippines — Hundreds of desperate residents remained trapped in this besieged southern Philippine city on Monday, as local militants loyal to the Islamic State and backed by foreign fighters stubbornly held their ground against government troops.
Troops have so far cleared just half of Marawi of militants from the Abu Sayyaf and Maute groups, but the insurgents have broken up into small groups and proved elusive, said Zia Alonto Adiong, a spokesman for the Lanao del Sur provincial government. The military’s inability to drive out the rebels has become a major challenge for the government of President Rodrigo Duterte, who declared martial law in the region last week in vowing to quash the insurgents.
In a sign that the standoff was turning into a long-term siege, Mr. Alonto said the province had imposed a nightly curfew and called on civilians to help the military fight and subdue the militants.
“Government forces are allowing citizens’ arrests,” he said. “We are calling on those who can to help us,” he told reporters in Marawi, as helicopters on bombing runs circled above this once bustling city of 200,000, which has now been reduced to a virtual ghost town where pockets of gunfire intermittently break the eerie silence.
The crisis appears to be spilling over to the nearby city of Iligan, with refugees from the fighting flowing in amid fears that insurgents could be hiding among them.
“Iligan City is now overflowing, crowded because it is the choke point, the gateway in and out of Marawi,” said Col. Alex Aduca, an army infantry commander.
“The terrorists are trying to withdraw, and those who can leave might attempt to enter Iligan by disguising themselves as evacuees,” he said. “We are carefully screening everyone, including evacuees, to make sure none of the rebels gets past us in disguise.”
As government forces focused on driving the rebels from Marawi, they also escorted dozens of civilians from the city using armored personnel carriers and military trucks with mounted machine guns.
As of Monday, 61 militants, 20 government troops and 19 civilians had died in the fighting, according to the military and the authorities. Sixteen of those civilians had been found dead Sunday, with one group dumped into a ravine and another found near a university. Volunteers said casualty numbers were likely to increase, with many bodies in places that had yet to be reached.
Hostilities erupted last week when the military and the police moved to arrest Isnilon Hapilon, the Islamic State’s anointed leader in the Philippines and head of an Abu Sayyaf faction, but were met by a 100-strong force of fighters that also included heavily armed insurgents from the allied Maute group. The military has said that militants from Indonesia, Malaysia and Singapore were among those taking part in the clashes.
The Maute fighters quickly took over much of the city, burning a cathedral and a hospital and kidnapping a Roman Catholic priest and several people whose fates remained unknown. They then spread out of the city, engaging troops in running gun battles.
The army had hoped to finish off the rebels quickly, but the militants mixed in among Marawi’s inhabitants, complicating government efforts to subdue them and rescue trapped citizens. Officials called on civilians to wear white or tie on white ribbons to indicate they were noncombatants.
“There are many people stranded inside the areas where we believe fighters are still roaming,” said Saripada Pacasum, the deputy of the provincial disaster council.
“Three women were texting us in the hotline from their basement. One said, ‘There are I.S. fighters inside our home,’” he said, referring to the Islamic State. “We told them to just hide and be silent.”
“We never heard back from them,” he added. “We have no word on the priest and the hostages.”
He added that some trapped civilians had called on the military “to stop the bombardment so that food and water could be brought in.”
On Monday, the atmosphere in Marawi was tense, with constant explosions sending evacuees into a panic. Evacuees also had to pass through checkpoints at several roadblocks to leave the city. Some were asked to submit to strip searches by government troops.
“We just want to join our relatives in Iligan,” said Norhayda Aziz, 23. “This place has been forsaken.”
On the road to Iligan, about 200 people, including children, were asked to get out of their vehicles and pass through a security checkpoint.
Amid the deepening crisis, Mr. Duterte faced calls not to use it as a pretext for strengthening his grip on the country. Last week, Mr. Duterte had warned that he might impose martial law on the whole country to stop the Islamist threat.
“No one is above the law, not even the president,” said Senator Francis Pangilinan, an opposition leader. “We oppose any violation of the Constitution on matters pertaining to the martial law declaration. To allow the president to disregard the Constitution is to open the gates to dictatorship.”