Media playback is unsupported on your device Media caption Over 1,000 troops have been battling to drive rebels out of Zamboanga

Fighting has resumed between government troops and Muslim rebels in the southern Philippines, despite a recently agreed ceasefire.

Officials said troops were battling to retake a series of villages near Zamboanga city, where members of the Moro National Liberation Front (MNLF) are holding about 100 people hostage.

More than 50 people have died in the violence, now in its sixth day.

Another 60,000 people have fled their homes and a curfew is in place.

Late on Friday, Vice-President Jejomar Binay said he had spoken by telephone to Nur Misuari, the MNLF leader who is pushing for an independent Islamic state in the southern Philippines.

Mr Binay said the rebel leader had agreed to a ceasefire as well as talks to resolve the Zamboanga standoff.

But analysts say it is unclear how this would work in practice, especially as Nur Misuari's whereabouts are unknown - and by Saturday morning it appeared that the ceasefire agreement had already broken down.

Image caption Government troops are fighting Muslim rebels in the streets of Zamboanga Image caption Scores of people have been injured in the violence Image caption An estimated 60,000 have been displaced from their homes Image caption Many have moved to the city's sports complex Image caption Others - many of whom are fishermen - have retreated to their boats for safety previous slide next slide

"The vice president is sad that his efforts to secure the release of the hostages in Zamboanga city did not prosper," Mr Binay's spokesman Joey Salgado said in a statement.

Clashes were reported in three districts of Zamboanga on Saturday - and also on the nearby island of Basilan.

Abigail Valte, a presidential spokeswoman, also accused the rebels of launching attacks throughout Friday night.

Military officials told Reuters news agency that troops had retaken a school which the rebels had used as a base. The soldiers reportedly found seven bodies inside the building.

Gunfire exchanges

President Benigno Aquino flew to Zamboanga on Friday to visit people displaced by the violence, now sheltering in a sports complex.

He said more clashes were expected, but that the rebels' "capability to inflict chaos here in Zamboanga city is diminishing".

More than 1,000 troops, backed by police, have been fighting to drive the MNLF out of the city and its surrounding villages since the rebels launched their attack on Monday.

Schools and shops have been closed, with only essential government offices open, according to aid agencies.

The MNLF was founded by Nur Misuari in 1971, with the goal of fighting the Philippine state for an independent Islamic nation.

The group then signed a peace agreement with the government in 1996.

But Nur Misuari has complained that his faction has been marginalised in a peace agreement currently being negotiated between the government and another insurgent group, the Moro Islamic Liberation Front.

Last month, he declared an independent Muslim state in the southern Philippines.