SEOUL, June 26 (Reuters) - South Korean President Yoon Suk-yeol will meet leaders of the United States and Japan on Wednesday during the North Atlantic Treaty Organization (NATO) summit in Madrid, an official at the presidential office said on Sunday.

The trilateral meeting, which would be the first such gathering since September 2017, is scheduled to for 2:30 p.m., though changes can be made, the official said.

President Yoon and Japanese Prime Minister Fumio Kishida are not likely to hold a separate meeting, the official added.

Separately, a Japanese government official also told Reuters that the three leaders will hold a meeting on June 29.

Earlier this week, South Korea said it planned to set up a delegation to NATO in Brussels as Seoul pushes to strengthen its partnership with the organisation and play a bigger role on the global stage.

Yoon, who was sworn in on May 10, will be the first South Korean president to attend a NATO summit, as the country, along with Japan, Australia and New Zealand, has been invited as the organisation's Asia-Pacific partners.

While the June 29-30 meeting in Madrid is expected to focus on the Ukraine crisis, Yoon plans to drum up international cooperation against North Korea's nuclear programme, the presidential office said.