The chief of a Philippines' Muslim rebel group that pledged allegiance to the Islamic State (Isis) terrorists has died.

Filipino officials said that Ameril Umbra Kato was buried on 14 April. He was replaced by Esmail Abubakar as the new leader of the Bangsamoro Islamic Freedom Movement (BIFF).

"Hopefully we can decimate their whole organisation and prevent them from becoming a spoiler," military chief of staff general Gregorio Pio Catapang was quoted by AP as saying.

The chief urged the group to sign a peace deal with the government, which was already endorsed by the Moro Islamic Liberation Front (MILF).

However, Kato's spokesman Abu Misry said his group will continue to fight. "We will never go back to the [Moro group] because it's no longer waging jihad," he said.

MILF is the largest Muslim group in the Philippines, and demands the independence of the Bangsamoro land in the southern region of the country. When MILF and government officials signed the peace deal, they agreed that Bangsamoro could become an independent Muslim land by 2016, if rebels stop carrying out attacks in the country.

It is believed that violence linked to the MILF's insurgence has killed some 120 people since 1976, when the group was formed from the Moro National Liberation Front (MNLF).

BIFF separated from the MILF some four years ago and vowed to continue to fight for independence and build an Islamic state.

While BIFF pledged allegiance to IS, MILF condemned the terrorists for their brutality and published an open letter criticising IS's "barbarism and savagery".