Filipino troops began driving the country’s Isis affiliate from southern city of Marawi in earnest on Thursday.
Backed by tanks and helicopter gunships, soldiers fought their way into the city of 200,000 inhabitants on the main southern island of Mindanao.
Military spokesman Lieutenant Colonel Jo-ar Herrera said: "Attack helicopters fired rockets in a precision attack. We want to finish this problem as soon as possible."
Reporters heard gunfire and saw plumes of smoke rising from the centre of the cordoned-off city as choppers roared overhead.
Col Herrera said some 21 people had been killed so far, including 13 Abu Sayyaf gunmen and five soldiers.
Lanao del Sur province Vice-Governor Mamintal Alonto Adiong said more than half the city’s population had fled.
Abu Sayyaf seized the city on Tuesday night after a failed security forces raid to capture the extremists’ commander and preacher Isnilon Hapilon.
They torched the city’s cathedral, took 14 hostages including a Catholic priest, and beheaded a police chief who the captured at a roadblock.
Catholics held a mass in the capital Manila yesterday for the the hostages and all Mindanao residents.
Col Herrera said authorities believed Mr Hapilon, who pledged the guerilla group’s allegiance to Isis in 2014, was still in the city.
Mr Hapilon leads an alliance of 10 extremist groups including the Maute, and has a $5 million US government bounty on his head.
He survived a previous attempt to eliminate him in a January airstrike.
"We have not seen any concrete evidence of material support from IS," military spokesman Brigadier General Restituto Padilla said on Thursday.
But he added that the smaller groups "are working to really get that recognition and funds, of course."
President Rodrigo Mr Duterte cut short his visit to Moscow on Wednesday to fly home and deal with the crisis.
That was not before he asked President Vladimir Putin for a “soft loan” to buy arms to combat the extremists “because the arms that we ordered from America were cancelled."
The US halted the sale of 27,000 rifles over western human rights groups’ allegations of thousands of extra-judicial killings in the country’s war on drug gangs.
But later yesterday US Ambassador Sung Kim tweeted: "As a proud ally, the US will continue to provide support for PH counterterrorism efforts."
And White House spokesman Sean Spicer condemned the Abu Sayyaf takeover, saying: "These cowardly terrorists killed Philippine law enforcement officials and endangered the lives of innocent citizens."
According to alleged transcripts a telephone conversation last month, leaked to the press on Wednesday, US President Donald Trump told Mr Duterte he was doing an "unbelievable job" in the fight against the narcotics trade.
The pair also discussed the confrontation with the Democratic People's Republic of Korea, with Mr Trump revealing the US Navy had two nuclear submarines in the region -- but didn't want to use them.
That drew predictable condemnation from the US Democratic Party opposition.
Congress Representative and House Foreign Affairs Committee member Eliot Engel said: "Today's reporting leaves me even more concerned by President Trump's strange fascination with dictators, his support for the extrajudicial killings central to President Duterte's 'drug war,' and his recklessness with sensitive information."
Backed by tanks and helicopter gunships, soldiers fought their way into the city of 200,000 inhabitants on the main southern island of Mindanao.
Military spokesman Lieutenant Colonel Jo-ar Herrera said: "Attack helicopters fired rockets in a precision attack. We want to finish this problem as soon as possible."
Reporters heard gunfire and saw plumes of smoke rising from the centre of the cordoned-off city as choppers roared overhead.
Col Herrera said some 21 people had been killed so far, including 13 Abu Sayyaf gunmen and five soldiers.
Lanao del Sur province Vice-Governor Mamintal Alonto Adiong said more than half the city’s population had fled.
Abu Sayyaf seized the city on Tuesday night after a failed security forces raid to capture the extremists’ commander and preacher Isnilon Hapilon.
They torched the city’s cathedral, took 14 hostages including a Catholic priest, and beheaded a police chief who the captured at a roadblock.
Catholics held a mass in the capital Manila yesterday for the the hostages and all Mindanao residents.
Col Herrera said authorities believed Mr Hapilon, who pledged the guerilla group’s allegiance to Isis in 2014, was still in the city.
Mr Hapilon leads an alliance of 10 extremist groups including the Maute, and has a $5 million US government bounty on his head.
He survived a previous attempt to eliminate him in a January airstrike.
"We have not seen any concrete evidence of material support from IS," military spokesman Brigadier General Restituto Padilla said on Thursday.
But he added that the smaller groups "are working to really get that recognition and funds, of course."
President Rodrigo Mr Duterte cut short his visit to Moscow on Wednesday to fly home and deal with the crisis.
That was not before he asked President Vladimir Putin for a “soft loan” to buy arms to combat the extremists “because the arms that we ordered from America were cancelled."
The US halted the sale of 27,000 rifles over western human rights groups’ allegations of thousands of extra-judicial killings in the country’s war on drug gangs.
But later yesterday US Ambassador Sung Kim tweeted: "As a proud ally, the US will continue to provide support for PH counterterrorism efforts."
And White House spokesman Sean Spicer condemned the Abu Sayyaf takeover, saying: "These cowardly terrorists killed Philippine law enforcement officials and endangered the lives of innocent citizens."
According to alleged transcripts a telephone conversation last month, leaked to the press on Wednesday, US President Donald Trump told Mr Duterte he was doing an "unbelievable job" in the fight against the narcotics trade.
The pair also discussed the confrontation with the Democratic People's Republic of Korea, with Mr Trump revealing the US Navy had two nuclear submarines in the region -- but didn't want to use them.
That drew predictable condemnation from the US Democratic Party opposition.
Congress Representative and House Foreign Affairs Committee member Eliot Engel said: "Today's reporting leaves me even more concerned by President Trump's strange fascination with dictators, his support for the extrajudicial killings central to President Duterte's 'drug war,' and his recklessness with sensitive information."