President Ma Ying-jeou said Taiwan would consider sanctions against the Philippines amid widespread public outrage at Manila over the shooting of a Taiwanese fisherman.
"We will definitely seek justice for our fisherman. We will not rule out the possibility of taking any kind of sanctions" against the Philippines, Ma said while inspecting a coastguard drill in central Taiwan.
"The Philippines shot an unarmed fishing boat. This is very brutal and cold-blooded," he said, reiterating Taipei's demand for Manila to apologise, apprehend the killer and compensate.
Some Taiwanese lawmakers urged the government to freeze the hiring of Philippine workers to protest after the Philippines admitted its coastguard had fired at a Taiwanese fishing boat.
Taiwanese authorities said 65-year-old fisherman Hung Shih-cheng was killed during Thursday's incident, which also left the boat riddled with more than 50 bullet holes.
Abigail Valte, a spokeswoman for Philippine President Benigno Aquino, told a government radio station that authorities had launched a "transparent and impartial investigation" into the incident.
She expressed hopes that economic ties with Taipei will not be affected and added that the coastguard crew involved in the incident have been temporarily suspended to ensure a fair probe.
"Let's wait for the investigation," Aquino's spokesman Ricky Carandang told AFP when asked to comment on Taiwan's sanctions threat.
Ma's government has come under pressure from the opposition and the media to take action, with the Philippines refusing to apologise and saying the coastguard was tackling illegal fishing.
Philippine coastguard spokesman Commander Armand Balilo said Friday the incident took place in Philippine waters and the Filipino personnel had been properly carrying out their duties to stop illegal fishing.
"If somebody died, they deserve our sympathy but not an apology," Balilo told reporters.
Hung's son has insisted that the boat did not cross into Philippine waters.
The Taipei-based China Times called the incident a "criminal case" and demanded Manila shoulder the full responsibility.
"The Philippines' uncivilised action apparently violated maritime convention, the Taiwan government must take strong counter moves to defend our fishermen's rights and prevent similar tragedy," it said in an editorial.
