Tanks roll in to tackle IS-linked militants in besieged Philippine city
Army tanks packed with soldiers have rolled into a southern Philippine city as gunfire and explosions rang out after militants torched buildings, seized more than a dozen Christian hostages and raised the black flag of Islamic State.
At least 21 people have died in fighting that erupted late on Tuesday when the army raided the Marawi hideout of Isnilon Hapilon, who is on Washington's list of most-wanted terrorists and has a 5 million dollar (£3.8 million) bounty on his head.
The operation went wrong as the militants called in reinforcements and swept through the mostly Muslim city of 200,000 people. Hapilon's whereabouts were not clear, but there was no indication he was captured in the raid.
President Rodrigo Duterte declared martial law across the southern third of the nation - home to 22 million people - and warned he may expand it nationwide.
He vowed to be "harsh", adding: "If I think that you should die, you will die. If you fight us, you will die. If there is open defiance, you will die. And if it means many people dying, so be it."
As details of the attack in Marawi city emerged, fears mounted that the largest Roman Catholic nation in Asia could be falling into a growing list of countries grappling with the influence of the Islamic State group in Syria and Iraq.
Thousands of people were fleeing the city on Thursday, jamming their belongings into cars. Plumes of black smoke rose in the distance and two air force helicopters could be seen flying over the city centre.
Although much of the city is sealed off, disturbing details were trickling out.
Mr Duterte said a local police chief was stopped at a militant checkpoint and beheaded. Military chief of staff General Eduardo Ano said the militants erected IS flags at several locations.
Marawi Bishop Edwin de la Pena said the militants forced their way into Marawi Cathedral and seized a Catholic priest, 10 worshippers and three church workers.
Martial law allows Mr Duterte to use the armed forces to carry out arrests, searches and detentions more rapidly.
He has repeatedly threatened to place the south, the scene of decades-long Muslim separatist uprisings, under martial law, but human rights groups have expressed fears that martial law powers could further embolden Mr Duterte, who they have accused of allowing extra-judicial killings of thousands of people in his crackdown on illegal drugs.
Hapilon, an Arabic-speaking Islamic preacher known for his expertise in commando assaults, pledged allegiance to IS in 2014. He is a commander of the Abu Sayyaf militant group and was wounded by a military air strike in January.