A group of 15 Taiwanese lawmakers -- led by Legislative Speaker Wang Jin-pyng and escorted by Defense Minister Lee Jye -- was aboard the Knox-class frigate when it departed Taiwan's eastern Suao port for the four-hour trip to an island group that both Tokyo and Taipei claim is in their exclusive economic zone.
Japan's representative in Taipei, Tadashi Ikeda, warned Taiwan on Monday that plans for the frigate's trip were inappropriate, saying the military should not be brought into a fishing dispute.
The 3,800-ton Fengyang, equipped with anti-ship missiles, was to sail 110
Taiwan has long avoided sending naval ships to protect its fishing boats against interference by Japanese patrol boats, fearing conflict with its neighbor and major trading partner.
Although Taiwan and Japan do not have diplomatic ties, Taiwan tries to maintain close relations with Tokyo, seeing it as an effective military counterweight to China, the island's biggest security threat. The decision to send the frigate follows complaints by fishermen that Taiwanese authorities have not done enough to protect them from Japanese patrol boats in the disputed area.
Japan often fines ship owners and impounds Taiwanese fishing vessels that enter the waters.