Philippine security forces early yesterday killed two top terrorists in South-east Asia during a fierce battle to reclaim Marawi from Muslim militants who have held parts of the southern city for nearly five months.

"Isnilon Hapilon and the last of the dreaded Maute brothers, Omarkhayam, are both dead," General Eduardo Ano, the military chief, told reporters yesterday.

Defence Secretary Delfin Lorenzana said security forces were now pursuing Malaysian Mahmud Ahmad, a former university lecturer who helped lead and finance the assault on Marawi, and at least eight other fighters from Malaysia and Indonesia.

With Hapilon dead, Mahmud, trained at an Al-Qaeda camp in Afghanistan, is believed to have replaced the 51-year-old at the helm, and is now the new regional leader for the Islamic State in Iraq and Syria (ISIS).

Omarkhayam Maute, with his brother Abdullah Maute, formed the group that supplied the bulk of the fighters who overran Marawi on May 23.

Gen Ano said Hapilon and Omarkhayam Maute were killed during an early-morning assault on a building where the two were holed up with dozens of hostages.

NOTORIOUS LEADERS

ISNILON HAPILON An Arab-speaking preacher, he was named by ISIS as "emir" of its South-east Asia branch last year. Born in 1966, Hapilon gained notoriety when he took part in kidnapping 20 hostages from a high-end resort in Palawan province in 2001. He later ascended the ranks of the small but brutal Abu Sayyaf group, known for high-profile kidnappings and killings of foreigners, to become its second-in-command. The US State Department placed a US$5 million (S$6.8 million) bounty on his head. Security forces had targeted Hapilon in large-scale military operations in 2008 and 2013, and had come close to killing him. But he would resurface each time. After he was designated as ISIS' top man in the region, Hapilon moved out of Abu Sayyaf's island strongholds in Sulu province to unite several bandit and terrorist groups in the southern Philippines and formed an ISIS "province" in Mindanao.

OMARKHAYAM MAUTE He studied at the Al-Azhar University in Cairo. He married an Indonesian, the daughter of a conservative Islamic cleric. A diplomat who met Maute in Cairo described him as being "like any other Filipino Muslim". "He seemed to me like the typical devout Muslim, judging by what he was wearing. He had a turban and a goatee… He was fluent in Arabic. I wouldn't say at the time that he came across as a radical," the diplomat told The Straits Times. With his brother Abdullah Maute, Omarkhayam Maute formed Dawla Islamiya in 2013. The group, which would later carry the brothers' names, pledged allegiance to ISIS last year and raised its profile after President Rodrigo Duterte took office. The group was blamed for bombing a street market in the President's home town of Davao City in September last year, killing 15 people. A foiled attack near the US Embassy in Manila last November revealed that it already had cells operating north of Manila. Raul Dancel

They were trying to move from one building to another in an attempt to escape when they were shot. Hapilon was hit in the torso, while Maute was shot in the head by a sniper. A photo released by the military showed part of Maute's head blown off.

Their bodies were recovered, but DNA tests will be carried out because of the huge rewards offered for their arrest.

Hapilon carried a US$5 million (S$6.8 million) bounty put up by the US Federal Bureau of Investigation and Philippine President Rodrigo Duterte has offered 10 million pesos (S$264,000). Maute, meanwhile, has a 5 million peso bounty on his head.

Gen Ano said the deaths of Hapilon and Maute meant the end for the remaining militants in Marawi.

"The Marawi crisis will be over sooner than later. The resistance, or what is left of it, will crumble. For the terrorists, it is a dead end. There is nowhere else to go for them," he said.

Mr Lorenzana said the government would "announce a cessation of hostilities within the week".

Martial law, however, will remain in force across the southern island of Mindanao.

"We still have to see," he said, adding that the terrorists still had cells across Mindanao. "But we will also get them."

Gen Ano said that with the fighting in Marawi nearing an end, security forces could focus on other Muslim extremists in the provinces of Sulu, Basilan and Maguindanao.

He also said he expected the deaths of Hapilon and Maute to reverberate across the Philippines.

"We consider the Maute brothers and Hapilon as centres of gravity. They were the strength that pulled together the whole organisation. Now that they are gone, the impact is a big debacle to the ISIS state they are trying to establish here," he said.

"They can't find another leader immediately in their infrastructure," he added. "In fact, what will happen is, since they are leaderless, their followers will abandon this cause or movement."

But Mr Lorenzana warned that all major cities in Mindanao were still vulnerable. "They don't need a big force to create trouble. You just need a small force occupying a building. All we can do is to be vigilant so that nothing of this sort can happen," he said.

More than 1,000 people, including militants, troops and civilians, have been killed in the fighting in and around Marawi. Thousands have fled their homes and large parts of the once-bustling city destroyed.

Surprise attack leads to months-long battle

May 23: Hundreds of Muslim militants overrun Marawi, a city of about 200,000, considered as centre of the Islamic faith in the southern island of Mindanao.

The surprise attack came after security forces attempted to arrest Isnilon Hapilon, the designated South-east Asia "emir" of the Islamic State in Iraq and Syria (ISIS). President Rodrigo Duterte places Mindanao under martial rule the next day. Marawi residents begin to evacuate.

June 2: A deadline set by Defence Secretary Delfin Lorenzana to end the conflict lapses. It is the first of many deadlines to lapse over the next few months.

July 29: After a two-month standoff, security forces finally gain a major victory. They seize two bridges leading to positions held by the militants in Marawi's now bombed-out business district. Sept 23: Security forces retake the last of three strategic bridges.

Oct 16: Government forces kill Hapilon and Omarkhayam Maute, and say the end to the fighting in the city is near.