The deployment of the THAAD missile defense system is emerging as a possible discussion topic when presidents Moon and Trump meet at the White House late this month.A senior U.S. official visiting Seoul this week has voiced Washington's commitment to addressing the issue. Connie Kim reports. Seoul and Washington will continue to work on the THAAD deployment issue so that a satisfactory outcome is achieved for both countries.That's what U.S. Under Secretary of State for Political Affairs Thomas Shannon told reporters wrapping up his talks with Vice Foreign Minister Lim Sung-nam.But he didn't give a direct answer as to whether the U.S.-made missile defense system was brought up during the talks."We have an ironclad commitment to our security and well-being and a commitment to THAAD deployment. So we are going to continue to work on this that is satisfactory for both countries."The suspension of the THAAD installation, pending a full-scale environmental impact assessment ordered by the presidential office, has been controversial, raising concerns in Washington that the system could be withdrawn after the assessment.Officially, Shannon is in Seoul for a three-day visit to arrange the details of the first ever summit between Presidents Moon and Trump.And he underscored the importance of the alliance and the two sides' commitment to a successful face-to-face meeting that will set the tone of bilateral relations for the coming years. "We did focus on the recent provocations of North Korea and its missile launches and its continuing misbehavior and underscored the ironclad commitment of both countries to our alliance and to our partnership to protect not just the people of Korea but alliance forces here in Korea and other important security partners in the region and beyond."Seoul's foreign ministry, for its part, raised hopes the summit will be an opportunity to ultimately resolve the security crisis on the Korean peninsula."Most experts in Seoul say the core of the summit is likely to be the suspended THAAD installation saying it will be critical for Seoul to thoroughly explain that domestic procedures for the missile defense system is underway... and to discuss the big picture of the two country's North Korea policy.Connie Kim, Arirang News."