The top diplomats of South Korea and Japan faced off Friday over Tokyo's decision to remove Seoul from its list of trusted trade partners during a regional forum in Thailand.

Foreign Minister Kang Kyung-wha and her Japanese counterpart, Taro Kono, traded barbs at the annual gathering, involving the 10-member Association of Southeast Asian Nations, their countries and China.

The meeting was held after Japan's Cabinet approved a decision to drop South Korea from the "whitelist" of 27 countries given preferential treatment in purchasing Japanese dual-use products that can be diverted for military use. It is the second retaliatory step in an escalating row over Japan's wartime forced labor.

"I am compelled to draw your attention to the decision made by Japan just this morning to remove my country from its list of trading partners that receive comprehensive export preferential treatment. And this (was done) in a very unilateral, arbitrary manner," Kang said at the ASEAN Plus Three meeting.

"We are gravely concerned by this decision to say the least with this coming in particular in the footsteps of an earlier decision that restricts some key export items to Korea," she added.

In a thinly veiled rebuke of Japan's export restrictions, Kang also stressed the importance of free trade.

"As the chair remarked at the opening of that meeting, we must choose to enlarge the piece of the pie that we all share through expanding free flow of trade and commerce rather than taking steps to shrink it.

"Unfortunately, that fundamental principle is being challenged in our own region."

Kono hit back, calling Kang's remarks a "complaint."

"I have not heard any complaints from our ASEAN friends about our export management measures," he said.

"ROK has been and is going to enjoy preferred status or equal status with our ASEAN friends and I don't know what is the source of the complaint by Foreign Minister Kang," he added, referring to South Korea using the acronym for its official name, Republic of Korea.

Kono went on to say, "Japan's necessary and legitimate review of its export control is fully compatible with the free trade regime, including the WTO agreement and relevant rules." WTO stands for World Trade Organization.

Seoul has criticized Japan's July 4 imposition of tighter restrictions on exports to South Korea of three key industrial materials vital to the manufacturing of semiconductors and displays, as going against principles of free trade that Tokyo has long championed and benefited from.

It also believes that the exclusion of Korea from the white list, as well as last month's export control measure, is political reprisal for last year's Supreme Court rulings that ordered Japanese firms to compensate South Korean victims of forced labor during Japan's 1910-45 colonization of the peninsula.

At the meeting, Chinese Foreign Minister Wang Yi called on APT countries to move toward greater cooperation and "firmly" uphold free trade.

"We hope and believe that APT countries will always give priority to cooperation and common development, unity and regional prosperity, address relevant differences appropriately and make East Asia a better place," he said.

"We need to firmly uphold free trade and make APT a front-runner for regional economic integration," he said. "We need to deepen people-to-people exchanges and make APT a platform for cultural harmony and co-existence. We need to jointly tackle risks and challenges and support peace and stability with APT cooperation." (Yonhap)