KORONADAL, Philippines (AP) _ Police arrested a man suspected of planting a bomb that killed 10 people in the southern Philippines, as the president warned Muslim rebels Monday that ``time was running out'' for them to cut ties with foreign terrorists.

Officials have blamed the Muslim separatist Moro Islamic Liberation Front for the bombing that ripped through Koronadal city's crowded market sidewalk Saturday. The death toll rose to 10 after a 60-year-old woman died of injuries Monday. Forty other people were hurt.

A police report said charges were being prepared against Alex Luntayan, 49, also known as Bapa Alim, a ``suspected bomber'' arrested in a raid on Koronadal's Muslim community Monday.

The report said police recovered grenades and ammunition. Police investigator Jonathan Jovero said 13 men were rounded up and questioned in the raid, and all except Luntayan were released. Jovero said the suspected bombers allegedly slept in Luntayan's house before Saturday's attack.

At least one other suspect was arrested Sunday, police said.

The rebels, who have been fighting for a separate Muslim homeland in the southern Philippines, denied involvement in the Koronadal bombing. But they say they have the right to defend themselves against a military offensive that drove them from a major camp in February. The government suspended talks with the rebels last week,

``I am deeply aggrieved by these continuing acts of inhumanity,'' Philippine President Gloria Macapagal Arroyo said in a speech after visiting the bombing site, where she lit a candle and offered flowers and prayers.

She said while the government has patiently tried to negotiate peacefully, the rebels have rebuffed those efforts with bomb attacks.

``There are well-meaning leaders who believe we must take that road (of peace) at all costs, but I cannot take the perpetual risk of putting the lives of Filipinos in graver peril,'' she said.

In an earlier statement, Arroyo said there was an ``obvious link'' between the bombing and recent MILF attacks.

``Time is running out for the MILF to prove its sincerity in the peace process,'' Arroyo said. ``It must cut the double talk and make a clear statement on whether it is allied with the Abu Sayyaf and foreign terrorist groups such as the Jemaah Islamiyah or the al-Qaida, or unequivocally reject them.''

Abu Sayyaf is a smaller, more violent Muslim rebel group operating in the southern Philippines. Jemaah Islamiyah, a regional group, has been blamed for bombings in Indonesia _ including the October 2002 Bali bombing that killed at least 202 people _ and thwarted attacks in Singapore. Both groups are thought to be connected to Osama bin Laden's al-Qaida terror network.

The government said Monday it was still mulling whether to declare the MILF a terrorist organization.

Foreign Secretary Blas Ople, speaking to ambassadors of the Organization of the Islamic Conference, said he believed the government should hold off doing so ``because it will undermine, destroy, the peace negotiations. But this will be contingent on the behavior of the MILF.''