Protesters stage die-in during a rally near the Presidential Palace to denounce the Martial Law declaration of President Rodrigo Duterte after Muslim militants laid a siege of Marawi city in southern Philippines for three weeks on June 12, in Manila, Philippines. The protesters also denounced the killings by Duterte’s bloody anti-drug crackdown. (AP)MARAWI CITY, Philippines, June 13, (RTRS): Fighting in Marawi City in the southern Philippines entered its fourth week on Tuesday with military officials conceding that troops were struggling to loosen the grip of Islamist fighters on downtown precincts despite relentless bombing.Military spokesman Brigadier General Restituto Padilla said the urban terrain was hampering the army’s progress because the rebels had hunkered down in built-up neighbourhoods, many of them with civilians they had taken as human shields.Hundreds of other civilians were still trapped in the ruins of the town and - facing capture, starvation or bombardment from above - several have braved sniper fire to dash across a bridge to safety. Some were shot dead, a few made it alive. Asked when the fighting would end, Padilla said: “I can’t give you an estimate because of compounding developments faced by ground commanders.” The military had set Monday, the Philippines’ independence day, as a target date to flush out the militants, both local and foreign fighters who have pledged allegiance to Islamic State.Flags were raised at ceremony in the town on the insurgency-plagued island of Mindanao, but heavy gunfire resumed early on Tuesday, and the military continued to target the militants with mortars and helicoptermounted machineguns.President Rodrigo Duterte, who declared martial law in Mindanao on May 23 - hours after several hundred fighters overran parts of the town and tried to seal it off to create an Islamic caliphate - did not show at any independence day events. Meanwhile, Islamist militants holding parts of a Philippine city are killing civilians who try to flee while using others as orderlies and cooks, authorities said Tuesday after the gunmen boasted of executions.There are up to 1,000 people still trapped in the parts of Marawi city that the militants control, the government said, three weeks after fighting erupted with gunmen going on a rampage and flying black flags of the Islamic State (IS) group.The militants have defied a USbacked military onslaught which has seen relentless bombing of the residential areas of Marawi where they are holed up. Authorities say 400 gunmen are estimated to be still there and using civilians as slaves.“Based on the revelations of the trapped civilians we have recovered (rescued), they are being used as orderlies to cook their food, to carry their munitions,” local military spokesman Lieutenant-Colonel Jo-ar Herrera told reporters. At least 26 civilians, 58 police or soldiers and 202 militants have been killed, according to the government.