MANILA - The Philippine government will stick to its policy of not negotiating with extremists allied with the Islamic State group that overran Marawi City in the southern Philippines in May, a government spokesman said on Tuesday.

Ernesto Abella said the talks initiated by Muslim religious leaders on Sunday to negotiate for the release of about 150 hostages in the besieged city in the spirit of Islamic holiday Eid al-Fitr were not sanctioned by the government, the military and the political leaders.

"The government policy is not to negotiate with terrorists. Any demands made inside, therefore, hold no basis," Abella said.

He stressed the need to punish the extremists who have wreaked havoc to the country's only Islamic city and forced more than 200,000 residents to flee to avoid being caught in the crossfire.

Meanwhile, the government said President Rodrigo Duterte is alive and well and experiencing no health problems, amid concerns about his disappearance from the public eye for unusually long periods this month.

Known for a busy schedule and lengthy speeches often several times a day, the 72-year-old Duterte's low profile has fueled rumors he is in declining health and that the government is trying to keep that under wraps. He was last seen in public a week ago.

What has created most intrigue is Duterte's absence during what is the biggest crisis of his year-old presidency, as the military battles for a sixth week to defeat IS-linked rebels in Marawi on his home island of Mindanao.

"First and foremost, he is alive and well, he is very well, he's just busy doing what he needs to do," Abella told reporters.

"As you've seen he's been very much in the public eye but being out of the public eye, that is when he is able to do office work, he signs papers, he reads, he consults, he's actually very busy.

"The thing that is very important to note is that he is on top of every situation, he is aware of what's happening, he's updated regularly, he reads, he listens and he's quite aware. This is just his working style."

Duterte's absences during June represent the longest periods he has been out of the spotlight. He was last seen on June 20 in two cities close to Marawi, visiting soldiers and evacuees.

That followed a three-day absence after a speech in which he said his health was "immaterial", amid raised eyebrows about his failure to appear in public for Independence Day celebrations on June 12.

Xinhua - Reuters