WASHINGTON, April 27 (Reuters) - South Korean President Yoon Suk Yeol told U.S. lawmakers on Thursday it is necessary to speed up trilateral cooperation with Japan and the United States to counter increasing North Korean nuclear threats, and said the world must not "shy away" from promoting freedom for the North. "Korea will never forget the great American heroes who fought with us to defend freedom," he said. On Wednesday, Yoon met President Joe Biden at the White House and the United States pledged to give South Korea more insight into its nuclear planning over any conflict with North Korea, amid anxiety over Pyongyang's growing arsenal of missiles and bombs. Yoon became the seventh South Korea leader to address Congress, underscoring the close relationship between Seoul and Washington. "We will actively work to safeguard the freedom of the people of Ukraine and support their efforts in reconstruction," he said.

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