Taiwan's premier Jiang Yi-huah is rejecting the Philippines president's apology for last week's shooting death of a Taiwanese fisherman by the coast guard.
Jiang says President Benigno Aquino's apology is unacceptable because it calls the shooting "unfortunate" and "unintentional."
Taiwan has imposed sanctions on the Philippines including recalling its envoy to Manila and freezing job permits for Philippines workers. Taiwan also plans to hold naval exercises in disputed waters.
Aquino sent a personal representative to Taiwan Wednesday to convey "his and the Filipino people's deep regret" to the family of the fisherman and the people of Taiwan. Taiwan also rejected an earlier apology.
A U.S. State Department spokesman says it is concerned by increased tensions between two neighboring democracies and close U.S. allies. It urges both to clarify disagreements and ensure maritime safety.
A Philippines Coast Guard ship opened fire on the fishing boat last Thursday in the South China Sea where both countries' economic interests overlap, killing a 65-year-old fisherman. The Philippines said it was acting in self-defense because the fisherman's boat was about to ram the coast guard vessel.
Taiwan and the Philippines, along with Brunei, China, Malaysia, and Vietnam all have competing claims to parts of the sea, which may be rich in oil and natural gas.