MANILA (Reuters) - The Philippines agreed on Friday to investigate the shooting death of a Taiwanese fisherman after criticism from Taipei and Beijing, but pledged increased efforts to prevent further incursions in its territorial seas.

A Philippines fisheries official said one of its vessels, acting under the threat of being rammed, opened fire on Thursday on a Taiwanese fishing boat about 170 nautical miles southeast of Taiwan, killing one person on board.

The Philippines and Taiwan, as well as China, Brunei, Malaysia and Vietnam, are embroiled in diplomatic rows over territory in the South China Sea, potentially rich in oil and gas and criss-crossed by crucial shipping lanes. The disputes have sometimes escalated to confrontation between vessels.

This incident occurred in waters north of the Philippine archipelago, where the economic zones of the Philippines and Taiwan -- extending 200 nautical miles from shore -- overlap.

Asis Perez, director of the Philippines' Bureau of Fisheries and Aquatic Resources, said a Taiwanese fishing boat, one of four vessels in the area, tried to ram the 30-metre surveillance boat after an attempt was made to board another fishing boat.

"This incident is very unfortunate, and efforts will be instituted to prevent similar occurrences. The government will increase our visibility in the area to prevent future incursion of our waters," Perez told reporters at the coast guard headquarters.

"We sympathize with the family of the fisherman who died and we assure them as well as the government of Taiwan of a transparent and impartial investigation."

The fisherman was killed as officers fired on the ship's engine to try to put it out of action.

The Philippine Coast Guard operates the small surveillance ships armed with a .30 caliber machinegun that are technically part of the country's fisheries bureau. A Philippine Navy spokesman earlier had denied navy involvement in the shooting.

"We have expressed strong condemnation to the Philippines, urging them to probe what happened, apologize, and arrest whoever was responsible," Taiwan Foreign Affairs Ministry spokeswoman Anna Kao told Reuters.

China, which considers Taiwan a breakaway province, also condemned the shooting.

"China demands that the Philippines immediately conduct an investigation and quickly offer an explanation. We express our heartfelt sympathies to the family of our deceased Taiwanese compatriot," Foreign Ministry spokeswoman Hua Chunying told reporters on Thursday.

(Reporting by Manuel Mogato in MANILA and Faith Hung in TAIPEI and Michael Martina in BEIJING; Editing by Ron Popeski)