Fighting intensified on Saturday in the southern Philippines between government troops and rogue Muslim separatists, shattering a ceasefire almost immediately as it was to go into effect and leaving many residents running low on supplies.
The army said 53 people, including 43 guerrillas, had been killed in the fighting, now in its sixth day in the port city of Zamboanga. Both President Benigno Aquino and his vice-president flew into the city to monitor operations.
Dozens have been wounded and more than 62,000 people displaced, with hundreds of homes razed and a hospital still in flames.
Rebels have fired on government positions and seized civilians to use as human shields.
The violence on Mindanao, the Philippines' most southern island and theater of four decades of violence, underscores the security challenge potential investors face in the mainly Roman Catholic country despite strong second quarter figures.
It also called into question a peace deal agreed last October with a larger Muslim rebel group, the Moro Islamic Liberation Front (MILF).
Late on Friday, Vice-President Jejomar Binay told Reuters he had spoken by telephone to Nur Misuari, leader of a rogue faction of the Moro National Liberation Front (MNLF), and they agreed to a ceasefire and talks to resolve the latest conflict.
Binay flew to Zamboanga and met Aquino, who had arrived a day earlier, though it was unclear what the two men discussed. Aquino, who oversaw last year's peace deal with the MILF rebels, has said nothing publicly about his vice-president's plan for talks to end the standoff.
Army spokesman Lieutenant-Colonel Ramon Zagala said the military was unaware of any ceasefire agreement with the rogue MNLF forces. "We have not received any order. We continue our operations until we are told otherwise," he said.
Heavy fighting broke out after midnight in a coastal village as soldiers retook rebel positions, killing four guerrillas.
Sporadic fighting struck three districts of Zamboanga through the morning and early afternoon. Skirmishes were also reported for the third day on the nearby island of Basilan, with the army saying one of its soldiers had been killed.
The gunfire subsided late in the afternoon, though rebel snipers kept up fire at both soldiers and civilians who attempted to cross government lines. The military said government troops had retaken a school used as a base by the rebels in a nearby village and found seven bodies inside.
Abigail Valte, a presidential spokeswoman, told reporters in Manila, 850 km (510 miles) to the north, that the ceasefire was never implemented. She accused the rebels of launching attacks through the night.
The rogue MNLF faction involved in the fighting opposed last year's peace deal struck with the larger MILF. It had signed a separate deal with the government in 1996, but later backed out, complaining the government had failed to abide by it.
Displaced city residents have been given temporary shelter.
But government social workers said some residents trapped in two schools were running out of food as heavy fighting had pinned down relief workers delivering supplies. Banks, shops, offices and some petrol stations remained closed.
Four decades of conflict in the south have killed 120,000 people, displaced two million and stunted growth in the poor but resource-rich area. Muslims account for about 10 percent of the total population of 97 million.
(Additional Reporting By Manuel Mogato in MANILA; Editing by Ron Popeski)