President Yoon Suk Yeol on Monday began a four-day state visit to the United Kingdom, invited by King Charles III, to mark the 140th anniversary of relations between the two countries this year.

During the visit, Yoon is poised to strengthen bilateral security and economic ties with the UK in the face of the wars in Ukraine and the Middle East. He will meet Prime Minister Rishi Sunak during the four-day trip, according to the presidential office on Sunday.

"Korea will serve as a nonpermanent member of the United Nations Security Council for the next two years, so there is growing room for security cooperation between South Korea and the UK," Yoon's spokesperson, Lee Do-woon, told reporters.

The two countries are also expected to announce the Korea-UK Accord, a comprehensive document that enshrines a broader bilateral relationship, Lee added. Yoon is the first foreign head of state invited for a state visit by the king since his coronation in May.

Before embarking on the state visit, Yoon told British newspaper The Telegraph in an interview that a "polycrisis" of multiple conflicts, partly due to North Korea's involvement in Russia's war with Ukraine, compelled him to seek "very close security cooperation" with the West, including the UK.

According to South Korea's presidential office and Buckingham Palace, Yoon and first lady Kim Keon Hee will be greeted by King Charles III during a ceremonial welcome at the Royal Pavilion on Horse Guards Parade in London on Tuesday.

After lunch at Buckingham Palace, Yoon and the first lady will take part in a wreath-laying ceremony at the Korean War Memorial in London. About 56,000 UK troops were sent to fight in the Korean War 1950-53 under the United Nations flag, making the participating UK army the second-largest after that of the United States. Nearly 1,200 UK soldiers were killed during the war.

The presidential couple will then visit Westminster Abbey to lay a wreath at the Grave of the Unknown Warrior and meet pensioners who served in the Korean War at the Royal Hospital Chelsea.

Yoon will travel to the Palace of Westminster to deliver an address to members of the Houses of Parliament. According to Lee, Yoon's speech will be delivered in English, his second English-language address to an overseas legislature following his speech to Congress in Washington in April.

"Speaking in the language of the country, Yoon seeks to win over the minds of politicians and citizens there," Lee told reporters Sunday.

On Wednesday, Yoon will deliver an opening address in front of entrepreneurs from South Korea and the UK at the "Shaping the Future: UK-Korea Business Forum," at Mansion House in London.

Yoon will also hold a summit with the UK prime minister at 10 Downing Street to discuss defense and security cooperation. Yoon and Sunak held talks for the first time in May on the sidelines of the Group of Seven summit in Hiroshima, Japan. They also briefly met in July on the margins of the North Atlantic Treaty Organization summit. According to Yoon's office, the summit will also revolve around strategic ties between Seoul and London in the fields of nuclear energy, artificial intelligence, cybersecurity, biotechnology, space, semiconductors and clean energy, among others.

Yoon on Thursday is also set to visit the Churchill War Rooms and bid farewell to King Charles III at Buckingham Palace, before leaving for Paris.

During his stay in Paris, Yoon plans to seek support from representatives of the Bureau International des Expositions for Busan's bid to host the World Expo in 2030. Busan is bidding to host the expo alongside Riyadh, Saudi Arabia and Rome.

Yoon returns to Seoul on Sunday.