Ahead of Defense Secretary Jim Mattis' visit later this week, South Korea has announced plans to develop a new surface-to-surface missile to inflict "unbearable costs" on North Korea in the event of war.
In a report last week to South Korea's National Assembly Defense Committee, the Republic of Korea (ROK) Army said the planned new missile, designated Hyunmoo IV, would be a more powerful version of two other types of surface-to-surface missiles now in South Korea's arsenal.
"We would use those three types of missiles as the first salvo of the missile strike and concentrate them during the initial phase of war to destroy North Korea's long-range artillery units and missiles located in ballistic missile operating area," the report said.
Under agreements with the U.S., South Korean missiles had been limited to warheads of 1,100 pounds and a range of 500 miles. The Hyunmoo IV reportedly would carry a warhead twice that size and have increased range.
In September, U.S. President Donald Trump and South Korean President Moon Jae-in agreed "in principle" to lift the limits on the South Korean warheads. The U.S. Defense Department has that agreement in principle under review.
Mattis and Joint Chiefs Chairman Gen. Joseph Dunford have backed up Trump's frequent statements that "all options are on the table" in dealing with the North Korean nuclear threat, but they have also warned of the horrific consequences of another war on the Korean peninsula.
Dunford has repeatedly pointed out that military action against the North by the U.S. and its South Korean ally would likely trigger a massive artillery and rocket barrage across the demilitarized zone by the North that would devastate Seoul and the 20 million people in the metropolitan region.
Mattis on Tuesday was in the Philippines for meetings of defense ministers of the Association of Southeast Asian Nations, known as ASEAN.
In his visit to Seoul later this week, "I will talk with my counterparts, discussing the regional security crisis caused by the reckless [North Korean] provocations but also discuss our respect for shared values," he told reporters.
Trump is scheduled to visit Japan, South Korea and China beginning next week.
In a background briefing Monday, a White House official said one of the president's priorities will be to pressure China to be more forceful in efforts to rein in North Korea's nuclear programs.