"Even if this takes time, (we) have to definitely achieve (that goal)".
Before the Singapore summit, the Trump administration said denuclearisation should start "without delay" and after the meeting, it spoke of the process beginning "very quickly".
According to the Security Council North Korea sanctions committee website, only Russian Federation and China have reported legitimate sales of some 14,000 tons of refined petroleum to North Korea in 2018. "In this situation, it is very unrealistic to expect North Korea to move forward with the denuclearization process without any compensation for years to come", Cheong said.
Since the end of the Korean War, more than 31,000 North Koreans fled to South Korea for political, economic and other reasons, according to South Korean government records.
"I don't think we should go forward with the assumption that all this is going to work", Coats said.
Subsequent negotiations between Washington and Pyongyang have so far not produced any significant progress.
After Pompeo travelled to Pyongyang this month for talks to seek progress, North Korea complained that the United States was making "gangster-like" demands for rapid denuclearisation.
"The economy is likely to get worse", said Kim Byung-yeon, an economics professor at Seoul National University and expert on the North Korean economy.
The North Korean officials were being recalled for a possible ambassadorial meeting, according to South Korea's Yonhap News Agency. However, the US has indicated it would veto any such measure.
"If necessary, penalties will be imposed". The president also famously called North Korea an "extraordinary threat" to the U.S., justifying more pressure on Pyongyang.
It asked the committee to notify all United Nations member states that North Korea has breached a refined petroleum cap of 500,000 barrels a year - imposed by the council in December - and order an immediate halt to all transfers.
China, which accounts for the vast majority of North Korea's foreign trade, has said it was enforcing the sanctions, despite skepticism from some analysts.
"Discussions are ongoing and they're going very, very well", Trump told reporters.
However, the timing of the handover and the number of sets remains to be returned is still uncertain, in spite of two days of talks between United States and North Korean officials on Sunday and Monday, said the official, who did not want to be identified.
North Korea has often used the women as a reason to rebuff South Korea's repeated request to allow elderly citizens split during the 1950-53 Korean War to reunite with each other briefly.
But as of mid-July, the repatriation has not happened.