(CNN) -- A Philippine government convoy was ambushed by gunmen Thursday in the same province that saw the bloody massacre of 57 people last month, a Philippine military spokesman said.
The convoy was on its way back from a raid on the compound of former governor Andal Ampatuan Sr. in Maguindanao province, Maj. Randolph Cabangbang said.
No one was injured in the attack, he said.
"They were about to take the evidence to General Santos City when they were ambushed in the same municipality (where) the massacre took place," Cabangbang said. "The convoy was able to return fire and the gunmen scampered," he added.
The attack occurred at 7:30 p.m. local time (6:30 a.m. ET) and Philippine military personnel were still in the area conducting search operations several hours later, he said.
"We surmise that these are men who are still loyal to the governor trying to recover what we took from the governor's compound," Cabangbang said.
Thousands of rounds of ammunition and several firearms were recovered from the compound, Cabangbang said.
Maguindanao province is the same place where 57 people, including 30 journalists, were massacred on November 23. That attack, authorities have said, was an apparent attempt to keep a political opponent of the Ampatuan clan from registering to run for governor.
Philippine police say that at least two people who were at the scene of the massacre have implicated a mayor as being involved in the killings, state media reported Thursday.
The two are among 161 suspects in the killings in the southern province.
Some of the suspects are in custody; others are being sought, the Philippines News Agency said.
Immediately after the killings, suspicion fell on Andal Ampatuan Jr., the mayor of Datu Unsay municipality and the son of the powerful governor of Maguindanao. Authorities have recommended that Ampatuan be charged with 25 counts of murder.
"We have two (witnesses). Because they were in the crime scene, these two have direct testimony linking the mayor to the crime," the country's National Police Director Raul Castaneda was quoted as saying by the news agency.
Also on Thursday, 75 civilians, including children, were kidnapped in the region where the massacre took place, authorities said.
Several rebel groups there are fighting for different causes.
Seventeen children and an adult were freed soon after, and negotiations continued to secure the release of the rest, said Army Capt. Enrico Ileto.
The abductions took place Thursday afternoon in Prosperidad, the capital of Agusan del Sur province.
The November 23 massacre took place on the other side of the island. There are no indications that the two incidents are related.
Alongside Muslim separatist groups that have been fighting for an independent Islamic state in the region, communist rebels are engaged in a 40-year insurgency there.
The Philippine Congress met Thursday for a second day in a joint session as lawmakers questioned President Gloria Macapagal Arroyo's Cabinet members about a martial law that was imposed on the province Friday.
The martial law allows arrests without a warrant. The army has said it is necessary to impose peace following what has been called a politically motivated massacre. Critics contend that it sets a dangerous precedent.
Violence in the run-up to elections is not uncommon in the country. The Maguindanao massacre, however, is the worst politically motivated violence in recent Philippine history, according to state media.
The victims included the wife and sister of political candidate Ismael "Toto" Mangudadatu, who had sent the women to file paperwork allowing him to run for governor of Maguindanao.
He said he had received threats from allies of Gov. Andal Ampatuan Sr., the father of the accused mayor, saying he would be kidnapped if he filed the papers himself.
Maguindanao is part of an autonomous region in predominantly Muslim Mindanao, which was set up in the 1990s to quell armed uprisings by people seeking an independent Muslim homeland in the predominantly Christian Asian nation.
CNN's Nick Valencia, Joyce Joseph and Sarita Harilela contributed to this report.