Siege of Marawi: Christians executed by Isis discovered in ravine outside Philippine city

Philippine forces found the bodies of what appeared to be eight executed civilians as authorities launched fresh airstrikes to drive militants linked to the Islamic State group out of a besieged southern city. The death toll from six days of fighting neared 100.

The crisis in Marawi, home to some 200,000 people, has grown increasingly dire as the militants offered fierce resistance, fending off a military that has unleashed attack helicopters, armoured vehicles and scores of soldiers.

The violence prompted President Rodrigo Duterte on Tuesday to declare 60 days of martial law in the southern Philippines, where a Muslim separatist rebellion has raged for decades. But the recent bloodshed in Marawi has raised fears that extremism is growing as smaller militant groups unify and align themselves with the Islamic State group.

Much of the city is a no-go zone, but as the military advances and more civilians escape, the scope of the battle is becoming clear.

Thousands of civilians have streamed out of Marawi and more than 2,000 were still trapped inside the city. Many sent desperate text messages begging to be rescued and reporting that their homes had been destroyed, said Zia Alonto Adiong, an official in Lanao del Sur, one of the country's poorest provinces.

"Have mercy on us, we don't have any more water to drink," read one of the messages, sent to a hotline set up for trapped residents.

Military spokesman Brig. Gen. Restituto Padilla said that combat operations were still going on, but that the militants were weakening.

Padilla said the bodies of four men, three women and a child were found near a road close to Mindanao State University in Marawi.

Eight other men were found gunned down and thrown into a shallow ravine early Sunday in Marawi's Emi village, said police officer Jamail Mangadang. A paper sign attached to one of the men indicated that the victims had "betrayed their faith," he said, identifying the men as civilians.

Mangadang said the eight men were bakers and carpenters who were evacuating to Iligan, a city near Marawi, but were intercepted by the militants. When they couldn't recite verses of the Quran because they were Christians, they were brought to the top of a ravine and shot to death, Mangadang said, citing the chief of a village where the victims lived.

In addition to the civilian deaths, Padilla said 61 militants, 11 soldiers and four police were among the dead.

The violence erupted Tuesday night when the government launched a raid to capture Isnilon Hapilon, who is on Washington's list of most-wanted terrorists. But the operation went awry and militants rampaged through the city, torching buildings and battling government forces in the streets.

A priest and several worshippers were taken hostage. There was no word on their condition.

Hapilon, an Islamic preacher, is a commander of the Abu Sayyaf militant group who pledged allegiance to the Islamic State group in 2014. He also heads an alliance of at least 10 smaller militant groups, including the Maute, which has a heavy presence in Marawi and has been instrumental in fighting off government forces in the current battles.

All of the groups are inspired by the Islamic State group. Defense Secretary Delfin Lorenzana told reporters that Hapilon has received funds from the Islamic State group.

Washington has offered a $5 million reward for information leading to Hapilon's capture.