MANILA, Philippines (AP) — Troops clashed with communist rebels in the southern Philippines Thursday amid a hunt for hundreds of guerrillas who attacked three nickel mining complexes, alarming the local mining industry.

An army soldier was killed and three others wounded in the gunbattle near Esperanza town in southern Agusan del Sur province, but troops captured a New People's Army encampment and 12 assault rifles and hit several of the undetermined number of rebels, military spokesman Col. Arnulfo Marcelo Burgos said.

The Maoist guerrillas retreated and were being pursued by troops. It was not immediately clear if the guerrillas were among the more than 200 rebels who laid siege on three nickel mining complexes Monday in Claver town in nearby Surigao del Norte province. They disarmed guards, briefly held employees and torched trucks, heavy equipment and company offices.

Those attacks, among the largest mounted by the rebels in recent years, sent the government scrambling to reassure mining companies and foreign investors by deploying an additional army battalion of 500 soldiers and about 100 commando troops from a U.S.-trained contingent to secure remote mines and hunt down the guerrillas. Additional air force helicopters were sent to back up troops.

"It was a big blow to the economic activity in the area," Marcelo said. "The massive forces there will ensure a safe and secure environment."

One of the companies, Taganito Mining Corp., was forced to temporarily shut down operations after the attack. The company is operated by Nickel Asia, the Philippines' biggest nickel producer, which is partly Japanese-owned.

Japanese Ambassador Toshinao Urabe said Wednesday that about 60 Japanese workers building a smelting plant at Taganito were not harmed in the attack.

"It's awful, I mean it's not only the damage to the equipment but the damage to the reputation of the Philippines that I'm worried (about)," Urabe said.

National police chief Nicanor Bartolome reassured a local group of top mining officials Thursday that the military and police had strengthened security in mining areas and were assessing what went wrong Monday.

During Monday's attacks, the rebels set up road blockades and laid explosives to stall reinforcement troops. They opened fire at an air force helicopter ferrying troops and ambushed a convoy of the region's highest-ranking police general, who escaped without injuries, Bartolome said.

Benjamin Philip Romualdez, president of the Chamber of Mines of the Philippines, said the attack was an "extreme challenge" to mining companies. "There was a huge loss and disruption to the industry," Romualdez said, adding the attacks sparked concerns for the safety of mining investments in the country.

The New People's Army, which is listed by Washington as a terrorist group, has accused mining companies of exploiting the country's resources and workers. The military has said rebel attacks on mining companies were part of extortion attempts.

Netherlands-based rebel leader Luis Jalandoni said President Benigno Aquino III sided with the mining companies by sending troops to secure them instead of protecting Surigao residents from what he called widespread pollution and exploitation of workers and resources by giant firms.

The Marxist rebels, estimated to number more than 4,000, have continued attacks despite resuming talks this year aimed at settling one of Asia's longest-running communist insurgencies. Philippine officials said they would continue with peace negotiations with the rebels despite Monday's attacks.