South Korean President Yoon Suk Yeol on Tuesday called former colonial ruler Japan a "partner" that shares his country's values and common interests as he aims to strengthen ties with Tokyo in response to North Korea's growing nuclear threats.
Relations between the North and South are at one of their lowest points in decades, with diplomacy stalled and North Korean leader Kim Jong Un calling for increased weapons development, including tactical nukes.
In response, Yoon has pulled South Korea closer to long-standing ally Washington while seeking to bury the hatchet with former colonial power Japan.
The three are set to hold a trilateral summit in the United States on Friday, during which the leaders are expected to announce plans for expanding military cooperation.
The summit "will set a new milestone in trilateral cooperation contributing to peace and prosperity on the Korean Peninsula and in the Indo Pacific region," Yoon said.
Seoul and Tokyo, key US security allies, have long been at odds over historical issues tied to Japan's brutal 1910-1945 occupation of the Korean peninsula, such as sexual slavery and forced labour.
But speaking at an event marking the anniversary of liberation from Japan's rule, Yoon said the two "are now partners who share universal values and pursue common interests".
He reiterated that Tokyo, Seoul and Washington must "share North Korea's nuclear weapons and missiles data in real-time".
"The seven rear bases provided to the United Nations Command(UNC) by the government of Japan serve as the greatest deterrent" to an invasion by the North, he added.
The three allies said in June that they aimed to launch before the end of 2023 a system allowing the sharing of real-time missile warning data.
-'Audacious plan'-
August 15 -- known in the South as Gwangbokjeol, or Liberation Day -- is the only public holiday celebrated in both North and South Korea, according to Seoul's National Institute for Unification Education.
On last year's anniversary, Yoon offered Pyongyang an "audacious" aid plan that would include food, energy and infrastructure help in return for the North abandoning its nuclear weapons programme.
Pyongyang has since ridiculed the offer, calling it the "height of absurdity" and a deal it would never accept, but Yoon on Tuesday said Seoul would "steadfastly implement" the plan and continue attempting to convince Pyongyang to return to dialogue.
North Korea's leader recently called for stepping up war preparations "in an offensive way" as well as a "drastic boost" in missile production.
Kim last month oversaw a dramatic military parade featuring new attack drones and Pyongyang's nuclear-capable intercontinental ballistic missiles, flanked by visiting Russian and Chinese officials.
Some experts said the attendance of Moscow's defense minister showed Russia's readiness to expand military cooperation with Pyongyang.
North Korean state media on Tuesday said Kim had exchanged letters with Russian President Vladimir Putin to mark the August 15 anniversary.
"This holiday is a symbol of bravery and heroism of the Red Army soldiers and the Korean patriots who fought together to liberate Korea from Japan's colonial rule," Putin told Kim in his letter, according to KCNA, adding: "I am sure that we will strengthen the bilateral cooperation in all fields."
Kim wrote to Putin: "The two countries will always emerge victorious, strongly supporting and cooperating with each other in the course of achieving their common goal and cause."
Last month, Putin hailed Pyongyang's "firm support for special military operations against Ukraine".
