MANILA, June 10 (Xinhua) -- Philippine security forces launched on Sunday airstrikes and ground assault on Islamist militants' lair in Maguindanao province in the southern part of the country.

Brig. Gen. Cirilito Sobejana, an army commander in charge of the operations, said the pre-dawn assaults on Liguasan marsh destroyed a bomb-making "factory" of the Bangsamoro Islamic Freedom Fighters (BIFF), a splinter group of the larger Moro Islamic Liberation Front (MILF).

Sobejana said there were up to 100 BIFF fighters in the targeted area during the assault.

Sobejana said the destruction of the facility where the BIFF members are making improvised explosive devices is a big loss to the militants' capability to produce bombs.

"We hit their factory, their bomb factory exploded. It was hit by our air assets. We employed all available air and artillery assets," Army spokesman Maj. Arvin Encinas said.

He said the BIFF militants were caught by surprise by the attack and scampered to escape the assaulting troops. The military is assessing the casualties in the attack, he added.

BIFF split with the MILF in 2010 to fight for a separatist Islamic state for Filipino Muslim minority in the Mindanao region. BIFF has up to 400 members, according to the military.

While MILF signed a peace agreement between the government on March 27, 2014 and the latter promised to establish a new autonomous Bangsamoro political entity on which the congress has been discussing for years.

The BIFF is among the several militant groups in Mindanao that pledged allegiance with the Islamic State of Iraq and Syria a few years ago. They are active in central Mindanao area, especially in Cotabato City, in Maguindanao, North Cotabato and Sultan Kudarat provinces.