MANILA - Former government auxiliary forces loyal to the powerful Ampatuan clan in Maguindanao have engaged the Philippine National Police in several clashes, Interior and Local Government Secretary Ronaldo Puno said Monday.

"There have been shooting incidents between these groups and the Philippine National Police. They have gone beyond just standing together in a crowd...They've engaged in actual firefights aganst the uniformed personnel," Puno said in press briefing.

Puno said the "rebels" were composed of former members of Civilian Volunteer Organizations (CVO) and Special Civilian Armed Auxiliary who refused to follow lawful authority in terms of disbanding their groups and surrendering their firearms. "They positioned themselves in municipalities to prevent the entry of lawful forces. These civilian auxiliaries became a separate group that was no longer following the chain of command," he said.

Lt. Gen. Raymundo Ferrer, Eastern Mindanao Command chief, earlier said some 3,000 armed followers of the Ampatuan clan remain a threat in Maguindanao despite the imposition of martial law.

"These (militiamen) are in hiding with their weapons. They have said they will fight and there are many of them," Ferrer said in a radio interview.

The armed group are followers of the Ampatuan family, which has ruled the province since 2001 and whose leaders are accused of being behind the November 23 massacre of 57 people.

The government said it was forced to impose martial law after Ampatuan forces threatened to attack if the leaders were taken into custody.

"They managed to slip out some guns and ammunition before martial law," Ferrer said.

"(They) are in a defensive position, and the information we have received is that they are prepared to fight the government."

Thousands of government forces have taken over the province since martial law was imposed.

They have carried out raids on Ampatuan properties and recovered an enormous array of military hardware, including anti-tank weapons and armored personnel carriers.

As of Sunday, 62 people had been arrested, including the clan patriarch Andal Ampatuan Snr and four other clan members.

His son, Andal Ampatuan Jr., was already in a Manila jail and charged with 25 counts of murder even before martial law was imposed.

Puno said the imposition of martial law allowed the national government to enter areas where weapons and ammunition were being stored by the Ampatuan clan. He said that of the 11 search warrants applied for in the investigation of the November 23 massacre, only one was approved in Cotabato City. With Agence France-Presse