Image copyright AFP Image caption BIFF rebels have rejected the recent peace accord between the government and the larger Muslim rebel group, MILF

At least 37 Philippine rebels have been killed in a two-day offensive in the south, the military says.

President Benigno Aquino said the offensive would protect villages from rebels in Maguindanao province.

The insurgents involved in fighting oppose a recent peace accord between the government and the larger Moro Islamic Liberation Front (MILF).

Under the new deal, MILF rebels will hand over their weapons in exchange for self-rule in parts of the south.

But insurgents belonging to the breakaway rebel Bangsamoro Islamic Freedom Fighters (BIFF) say MILF compromised too much in the truce.

The group, which comprises a few hundred militants, say they will continue their uprising because the deal did not lead to a separate homeland for minority Muslims in the south.

'Degrade abilities'

BIFF rebels have carried out several deadly attacks in recent years in a bid to derail peace talks.

Speaking to reporters, President Aquino said troops were aiming "to seriously degrade their abilities to again act as spoilers''.

Local military spokesman Col Dickson Hermoso said 12 of the dead rebels have so far been identified, with more bodies discovered in graves near a village in Maguindanao.

One soldier was killed and four others wounded in a blast outside a mosque on Tuesday, he added.

But BIFF spokesman Abu Misri has denied any deaths, saying seven insurgents were wounded in army shelling and helicopter rocket fire.

Image copyright AFP Image caption Last week's agreement is set to pave the way for a final and comprehensive peace treaty

Hundreds of villagers are believed to have fled the fighting in the southern province.

The accord with the MILF, which was agreed last week in Kuala Lumpur, is the fourth part of a roadmap for peace set out in October 2012.

Tens of thousands of people have been killed over the past four decades of separatist fighting.

The MILF, created after a split with another rebel group in 1977, originally wanted an independent Muslim state, but dropped this demand.

The Philippines has faced separatist movements for decades in Mindanao, where the MILF is based, and in Jolo, home to the radical Islamist Abu Sayyaf group, which is reputedly linked to al-Qaeda.

Communist rebels also waged a guerrilla campaign over parts of the country from 1969.