SEOUL - ROK President Moon Jae-in and US President Donald Trump held discussions on Sunday to ensure that the DPRK-US summit remains on track after DPRK threatened to pull out of the high-level talks.

Moon and Trump spoke over the phone for about 20 minutes, and exchanged their views on DPRK's recent reactions, ROK's presidential office said without elaborating.

"The two leaders will work closely and unwaveringly for the successful hosting of the DPRK- US summit set on June 12, including the upcoming ROK-US summit," the presidential official said.

Moon and Trump are set to meet on Tuesday in Washington before DPRK leader Kim Jong-un meets with Trump on June 12 in Singapore.

Although a historic inter-Korean summit in late April raised hopes of reconciliation, DPRK showed a dramatic change in tone in recent days.

DPRK's chief negotiator Ri Son Gwon said on Thursday it would not hold talks with ROK unless their demands were met, taking issue with the US-ROK air combat drills known as Max Thunder. It came a day after it threatened to pull out of the summit with the United States.

Further dampening the mood, a spokesman for DPRK's Red Cross Society demanded on Saturday that ROK's government should send DPRK's female restaurant workers back to their home "without delay" to show the will to improve the inter-Korean ties, the DPRK's Korea Central News agency said.

A dozen DPRK's restaurant workers came to ROK in 2016 from China, and DPRK had urged to send them back claiming they were abducted by the ROK, even though the ROK has said the 12 workers decided to defect of their own free will.

Lee Dong-bok, a researcher at New Asia Research Institution, said part of the reason for the DPRK's demands of the repatriation is to divide ROK's public opinion over the 12 workers.

"It is also to pressure the Moon government to agree to its demand so that ROK can keep up the momentum for the DPRK-US summit meeting," Lee said.

Reuters