The dialogue was suspended by increased cross-border tension following the North's missile and nuclear activities.
Reducing illegal revenue streams in North Korea has become more important because North Korea has set up the first successful Ballistic missile (ICBM), capable of reaching Alaska; US Secretary of State Rex Tillerson has intensified US efforts to curb violations of global law in relations with Pyongyang.
It conducted the first test of an intercontinental ballistic missile earlier this month, claiming to have mastered the technology to mount a nuclear warhead on the missile. Analysts saySouth Korea may be willing to suspend loudspeaker broadcasts at the border that are highly critical of the North Korean leader to re-establish contact. Oil products are sold by weight in North Korea. Indeed, in its prolific use of stamps to bring in revenue, North Korea and the US share some rare common ground. The missile defense program is meant to shoot down North Korea's shorter range ballistic missiles.
Maruyama said Japan is encouraging China to play "a greater role" in pressuring North Korea to halt its provocative actions and comply with Security Council resolutions.
The three leaders also agreed to press for early adoption of a new United Nations sanctions resolution to demonstrate to North Korea that "there are serious consequences for its destabilizing, provocative and escalatory actions".
A strategic balance can be broken when North Korea succeeds in developing an ICBM capable of striking the US mainland in a few years.
"Most missile programs, when they begin, have a 50% or greater failure rate".
Cho Myoung-gyon, head of the Unification Ministry, which handles inter-Korean relations, later said in a press briefing Monday that South Korea had left enough wiggle room for the North, adding that the local government would flesh things out once Pyongyang reacts. North Korea has never acknowledged the launch.
Fresh US sanctions would be aimed at sending a message to Beijing of Washington's resolve to act further on its own.
North Korea gets most of its fuel from China, with some coming from Russian Federation.
On the separate offer to hold family reunions, the Korean Red Cross asked the North to hold relevant talks on August 1 at the Peace House, a South Korea-controlled building in the truce village, known as the equivalent to North Korea's Tongilgak. Both sides resumed the offensive campaign after the North's fourth nuclear test in January.
The US maintains nearly 29,000 military servicemen stationed in South Korea, claiming they act as deterrence against potential aggression from North Korea.
When she told other North Korean defectors about her plan to return to the North, they held her back, she asserted, saying she would be shot to death for talking ill of the Kim leadership on South Korean television.