FILE PHOTO: South Korea's first lady Kim Jung-sook, South Korean President Moon Jae-in, North Korean leader Kim Jong Un and his wife Ri Sol Ju toast during a luncheon, in this photo released by North Korea's Korean Central News Agency (KCNA) on September 21, 2018. KCNA via REUTERS

SEOUL (Reuters) - South Korean military transport aircraft began a tangerine airlift to North Korea on Sunday, the first of a gift of 200 tons of the fruit from the southern island of Jeju, South Korea’s presidential Blue House said.

The present comes after the North Koreans gave South Korean President Moon Jae-in two tonnes of pricey pine mushrooms after a summit with North Korean leader Kim Jong Un in Pyongyang in September.

North Korea has pursued nuclear and missile program in defiance of U.N. sanctions and South Korean officials said last week they had tested the mushrooms for radiation after an opposition lawmaker complained.

The Jeju tangerines were packed in 20,000 boxes and will be flown to Pyongyang by four C-130 aircraft during multiple flights on Sunday and Monday, the Blue House said in a statement.

Several senior South Korean officials, including Vice Unification Minister Chun Hae-sung and presidential secretary for unification policy Suh Ho, flew to Pyongyang to deliver the first shipment.

North Korean leader Kim faces continued international pressure over his weapons program.

He vowed to work toward denuclearization during his historic June summit with U.S. President Donald Trump, but Pyongyang’s actions have fallen short of U.S. demands for irreversible steps to scrap its arsenal, including a full disclosure of nuclear facilities and materials.

That has left inter-Korean efforts limited by international and unilateral sanctions that bar many forms of economic interaction with North Korea.

But South and North Korea have conducted a number of inter-Korean projects designed to lower tensions, including joint sports and cultural events, closing some guardposts along their shared border, and regular high-level negotiations.