SEOUL/TOKYO - South Korea's new President Lee Jae-myung and Japanese Prime Minister Shigeru Ishiba vowed to deepen their relationship as the pair met for their first summit.

The two leaders spoke on the sidelines of the G7 meeting in Canada on Tuesday.

"Under the current strategic environment, the importance of Japan-South Korea relations and Japan-US-South Korea cooperation has not changed at all - rather, it has become more important," Ishiba said later at a press conference.

Lee said the two countries have an "inseparable" relationship like "neighbours who share a front yard."

The leaders discussed maintaining and strengthening trilateral cooperation with the United States, his office said in a statement.

Ties between the US allies have often been strained, rooted in historical disputes stemming from Japan's colonial rule over the Korean peninsula from 1910-1945.

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The United States has pressed the two countries to cooperate more closely to confront regional challenges.

Lee told Ishiba that cooperation would be mutually beneficial amid difficulties in the international trade environment and called for the improvement of ties in a "future-oriented manner".

In recent years, Lee had been harshly critical of efforts by his predecessor, conservative Yoon Suk-yeol, to mend ties with Tokyo. 

Lee's visit to Canada for the G7 summit marks his first international trip as president, since winning the June 3 snap presidential election called after Yoon was impeached and removed for briefly imposing martial law last year.

During the summit, Lee also met with other world leaders, including British Prime Minister Keir Starmer, where he called for progress on updating the free trade agreement between the two countries, according to Lee's office.

In a meeting with Indian Prime Minister Narendra Modi, Lee promised to deepen strategic cooperation and highlighted South Korean investments in the South Asian country.