Taiwan on Friday called for calm and promised to protect Filipinos on the island amid widespread anger toward the Philippines over the killing of a Taiwanese fisherman.

Taiwan's authority in charge of external affairs on Friday again urged Manila to provide a concrete response to the killing of the fisherman, adding that the incident possibly involves criminal proceedings and violates the United Nations Convention on the Law of the Sea.

"Although the Philippines has expressed deep regret and apologized over the incident, the matter of compensation for the victim's family, as well as authorization, remain unclear," it said in a statement.

Anti-Manila sentiments mounted after a 65-year-old fisherman was shot dead last week by Philippine coast guards.

Taiwan media have reported an attack on a Filipino, tourists canceling planned visits to the Philippines and some supermarkets removing food from the Philippines from their shelves.

Taiwan's ETTV cable news channel reported that a Filipino was allegedly attacked by four Taiwanese wielding iron bars as he went to work in southern Taiwan. He was treated in hospital for a facial injury.

Amadeo Perez, the Philippine representative to Taiwan, advised Thursday after returning from Taipei that thousands of Filipino workers in Taiwan should eat at home and avoid the streets, AP reported.

"We will continue negotiating the issue with the Philippines and I hope everyone can calmly and peacefully resolve the issue to avoid hurting bilateral ties," Taiwan leader Ma Ying-jeou was quoted as saying by AFP.

Ma said he has instructed relevant units to protect some 87,000 Filipinos living and working on the island to ensure they are not harmed.

David Lin, the island's chief official in charge of external affairs, Friday also urged calm at a press conference aimed at seeking more support in the lingering dispute.

Taiwan has rejected Manila's claims that the incident took place in Philippine waters and that it was "unintended," while Ma described the incident as "cold-blooded murder."

"If (Philippine) civil servants used automatic weapons to fire at unarmed fishing boats that didn't take provocative moves, this was not carrying out their job duties. This is cold-blooded murder," Ma said.

Manila was urged to show sincerity and issue a formal apology, provide compensation for losses, investigate the incident promptly and thoroughly punish the perpetrator, and initiate fishery talks as soon as possible.

Taiwan on Wednesday announced a second wave of sanctions targeting Manila after it rejected an "insincere" Philippine apology and decided to freeze applications by Filipinos to work in the island. It also recalled its representative to the Philippines.

Taiwan's tough stance is expected to be maintained until Manila offers a clearer and more reasonable response to the incident at a higher level, Su Hao, director of the Asia-Pacific Research Center at the China Foreign Affairs University, told the Global Times.

Su said if the dispute continues to escalate, the US might exert some pressure although Washington does not want to pick a side for fear of harming its own interests.

The US said on Wednesday it is concerned with the increase in tensions between Taiwan and the Philippines and urged them to work through their differences as quickly as possible. But Washington has so far stopped short of condemning the Philippines over the killing of the fisherman.