SHARIFF AGUAK, Philippines - The Philippine government on Monday promised it would immediately lift martial law in Maguindanao once a powerful Muslim clan accused of a political massacre is fully neutralized.

"There is no need for an extended martial law," Defense Secretary Norberto Gonzales told reporters in Shariff Aguak, the capital of Maguindanao province.

President Gloria Arroyo imposed martial law on Maguindanao on Friday night after the Ampatuan clan threatened to use its massive private army if its leaders were arrested.

The Ampatuans are accused of being behind the November 23 killings of members of a rival family and a group of journalists.

Arroyo had given police and military orders to arrest the masterminds and disarm the rebel force, Gonzales said.

"What she wants is once we accomplish this, right away martial law will be lifted," he said.

One clan leader, Andal Ampatuan Jr., was detained and charged with 25 counts of murder days after the crime. His father, Andal Ampatuan Sr., and four other members were apprehended Saturday.

While security forces have seized a huge volume of military hardware, the military said about 3,000 armed followers of the Ampatuans had escaped into the hills and remained a threat.

Some of these gunmen on Sunday evening attacked patrolling police commandos, triggering a brief gun battle but no casualties.

Arroyo's declaration of martial law has raised fears from some critics that the unpopular president may seek to expand it to cover the entire country.

Rights groups say Arroyo, who is to step down next year, is taking a leaf from the 20-year rule of dictator Ferdinand Marcos.

Marcos used martial law from 1972 to 1981 to jail thousands of political opponents and to perpetuate his one-man rule. He was finally toppled by the "people power" revolution in 1986.

The Congress is expected to convene a special session on Tuesday to decide whether to back or reject Arroyo's martial law for Maguindanao.