In this photo taken from video released by the Russian Defense Ministry on Thursday, Oct. 24, Russian soldiers patrol a village in the Russian - Ukrainian border area in ​​the Kursk region, Russia. (AP-Yonhap)

President Yoon Suk Yeol's office confirmed it was notified of Ukraine's plan to use US-made long-range supersonic ballistic missiles to strike Russia's Kursk region before US President Joe Biden authorized the change.

Asked if there was any coordination before Biden's announcement Sunday, a senior official of South Korea's presidential office told reporters in Rio de Janeiro, Brazil, Monday that Washington "notified Seoul that it was to give (Ukraine) permission for longer-range (weapons provided to Ukraine by the US) capable of targeting Russian territory prior to its announcement."

The official added that Biden's decision "was something shared with Seoul, which did not require any of Seoul's involvement or action."

The comments apparently referenced US-made Army Tactical Missile Systems (ATACMS), missiles whose US manufacturer claims have a maximum range of 300 kilometers.

On Sunday local time, Biden approved Ukraine's use of ATACMS for limited strikes in Russia's Kursk region, where the intelligence authorities of South Korea believe a throng of North Korean troops are stationed to fight against Ukrainian forces on battlefields near eastern Ukraine.

When asked about the possible supply of South Korean-made weapons to Ukraine, a presidential official said that Seoul has yet to begin talks with its Kyiv counterparts and that South Korea will make a decision once a Ukrainian special envoy arrives in Seoul.

The Seoul official added that ahead of Trump's inauguration in January, Russia will do all it can in Ukraine to win more territory before possible peace talks.

The comments came during President Yoon's visit to Rio de Janeiro to attend the Group of 20 summit.

On ties between South Korea and China, a senior presidential official said that "maintaining high-level talks and coordination is the most crucial part."

The official added that Seoul was pleased to see "its high-level talks with China becoming more frequent and engaging in discussions more deeply," adding that Seoul has continued to "put in efforts to develop the relationship with China in a mutually beneficial way."

On Monday, Yoon during the G-20 meeting unveiled plans for South Korea to contribute 845.6 billion won ($608.2 million) to the International Development Association this year, up 45 percent from its previous contribution three years ago.

Yoon also said South Korea would join the Global Alliance Against Hunger and Poverty and carry out $10 million in funding to the initiative by the end of this year.

Yoon also met Mexico's President Claudia Sheinbaum, Indonesian President Prabowo Subianto, Turkish President Recep Tayyip Erdogan and Australian Prime Minister Anthony Albanese Monday at a multilateral meeting of MIKTA on the occasion of the G-20 summit.

Yoon is likely to return to Seoul on Thursday, according to his office.