June 19 (UPI) -- U.S. Joint Chiefs of Staff Chairman Gen. Joseph Dunford said diplomacy and economic pressure are the primary ways the United States is to respond to North Korea's nuclear and missile threats, and that China is key to the denuclearization process.
Dunford made the remarks as the State Department said Monday that it plans to call on China to tighten sanctions against North Korea.
"A key element in...denuclearizing the peninsula would be the cooperation of China," Dunford said at the National Press Club in Washington, D.C. "It is a bit early, probably, to judge how far we've come in the past four to five weeks, but that's a critical piece."
The Joint Chiefs chairman said the Pentagon regards Kim Jong Un's nuclear and missile development as a threat and stands prepared to respond to a military offensive that cannot be blocked by deterrence.
But he added the Defense Department continues to support efforts in increasing economic and diplomatic pressure by U.S. State Secretary Rex Tillerson, through the pursuit of "open" and "aggressive" dialogue ongoing between the two departments.
Pressure on North Korea is a key issue to be discussed during the U.S.-China Security Dialogue to be held in Washington, D.C. on Wednesday, according to the State Department.
Acting Assistant Secretary of State for East Asian and Pacific Affairs Susan Thornton said Monday North Korea would be a "top priority" in the bilateral discussions.
"The United States remains committed to holding North Korea accountable for its flagrant and repeated disregard for multiple United Nations Security Council resolutions which expressly prohibit its ballistic missile and nuclear programs," Thornton said. "We continue to urge China to exert its unique leverage as North Korea's largest trading partner, including by fully implementing all U.N. Security Council sanctions."
Thornton also said the State Department hopes the three other detained Americans can "come home soon," hours before Otto Warmbier, the U.S. college student who was detained in North Korea for more than a year, died while receiving intensive care in Cincinnati, Ohio.
"Melania and I offer our deepest condolences to the family of Otto Warmbier on his untimely passing. There is nothing more tragic for a parent than to lose a child in the prime of life," the president said in a statement.