Seven militiamen were killed in an ambush laid by MILF rebels near the town of Upi in the province of Maguindanao early Saturday morning, the ABS-CBN news channel reported.

Government troops immediately launched retaliatory air strikes against MILF positions in the area and killed 12 rebels, it quoted military officers as saying.

The military also reportedly killed four MILF members and captured six others in a preemptive raid against the rebels in Datu Paglas, another town in Maguindanao.

President Gloria Macapagal-Arroyo on Friday rejected a 10-day unilateral ceasefire offered by the MILF, calling it a "ploy and tactical ruse" to buy time.

"The (military's) punitive actions will continue until we are assured that our far-flung communities are safe from harassment," she said.

The MILF on Wednesday declared the unilateral truce effective on June 2, but the rebels attacked military positions in the province of North Cotaba to the next day, which the military said left at least five civilians dead.

On May 17, President Arroyo ordered the military to launch selective punitive assaults against the MILF, which was blamed for a series of bombings and raids in the southern Philippines that has left more than 100 people dead since March.

The 12,000-strong MILF, the biggest rebel group in the country, has been fighting for an independent Islamic state in the south since 1978.

(Xinhua News Agency June 1, 2003)