Updated

The director of the U.S. Peace Corps will monitor the search for a volunteer missing for a week in a remote northern Philippine village while hiking solo, officials said Monday.

Ronald Tschetter was to arrive in Manila late Monday then travel to the township of Banaue on Tuesday to meet with American and Filipino authorities involved in the search for Peace Corps volunteer Julia Campbell, a U.S. Embassy statement said.

Philippine authorities said they have beefed up a mountain search for the 40-year-old U.S. Peace Corps volunteer from Fairfax, Virginia, but have found no new clues on her whereabouts.

Thirty police joined 50 other officers, U.S. Embassy personnel, army troops and local travel guides in combing forests and hiking trails for Campbell, said regional police Chief Superintendent Raul Gonzales.

She was last seen April 8 in Banaue in Ifugao province, about 160 miles north of Manila, where she had planned to hike alone to the area's famed mountainside rice terraces, said U.S. Embassy spokesman Matthew Lussenhop.

Gonzales said Campbell was last seen around 5 p.m. of that day when she stopped to buy soft drinks from a store in the village of Batad.

"She loves to walk and she could have slid and fallen on the steep cliffs there, or she could have been taken by some locals," Gonzales said in a telephone interview. "We are looking at all of that in our investigation."

The embassy appealed to the public for any information on the woman, and offered a reward.

Several thousand missing-person flyers have been posted in the area and searches were being conducted on foot and by helicopter, Lussenhop said.

Soldiers based in Banaue joined the search on Saturday, Army Maj. Gen. Rodrigo Maclang said. Military helicopters were flying over the rugged terrain, but Gonzales said fog obscured the view.

Residents told the military that Campbell arrived on April 8 by motorcycle taxi at a road junction leading to Batad, from where she planned to hike to a spot to view the rice terraces, Maclang said.

She had also contacted a local masseuse to meet her in Batad, but did not show up for her appointment, Maclang said.

Campbell had a bus reservation to go back to Manila on April 9 to catch a flight the following day. He did not know where she was headed to from the Philippine capital, he said.

There is only a small military presence in the area because "it is not a major concern now with regard to the (communist) insurgency," Maclang said.

Campbell is one of 137 Peace Corps volunteers currently in the Philippines. She has been teaching college students in Albay province's Legazpi city, southeast of Manila, since March 2005.

In 1990, the NPA seized Peace Corps volunteer Timothy Swanson and held him for 50 days on central Negros island. He was later released unharmed.

In June that year, the U.S. government ordered the evacuation of Peace Corps workers from the Philippines after receiving intelligence that rebels may try to kill or kidnap them. But by that time, Swanson already was in rebel hands.