Muslim fighters holding scores of hostages in the southern Philippines have demanded international mediation, according to a Philippine official.

The rebels, angered by a broken peace deal with the government, are using a dozen of the civilian hostages as human shields near the port city of Zamboanga.

Troops surrounded the fighters and their hostages in four coastal villages on Wednesday.

In another part of the city, three wounded rebels were arrested after exchanging gunfire with police manning a road block to stop the rebels from occupying other districts.

Last month, the Moro National Liberation Front (MNLF) issued new threats to secede by establishing its own republic.

However, its leader, Nur Misuari, has not appeared in public or issued any statement since about 200 of his alleged followers barged into Zamboanga City's coast early on Monday and clashed with soldiers and police.

The fighting left at least nine people dead and several wounded.

The rebels took scores of residents hostage, holding them in houses and a mosque that have been ringed by troops.

President Benigno Aquino III said the top priority was the safety of the hostages and residents of the city.

Mar Roxas, Philippine interior secretary, said officials had opened talks with the rebels "at different levels", including a commander loyal to Misuari, but added there had been no breakthrough.

The MNLF signed a 1996 peace accord with the government, but many of its fighters held on to their arms and accused officials of reneging on a promise to develop an autonomous region for minority Muslims in the south of the predominantly Roman Catholic Philippines.

The group has said it was being left out in government's negotiations with another fighter group, the Moro Islamic Liberation Front (MILF), which broke away from the MNLF in the early 1980s.

The 11,000-strong MNLF has engaged the Philippine government in Malaysian-brokered peace talks, which have progressed recently towards a new Muslim autonomy deal.

The decades-old insurgency by Muslim fighters in the southern Philippines has killed about 150,000 people.