President Trump holds a joint press conference with Sheikh Sabah Al Ahmad Al Sabah of Kuwait.
Trump on Thursday also seemingly touted his administration's success against ISIS compared with his predecessor, former President Obama.
"What we do is kill ISIS," Trump said of America's involvement in Syria. "We have done better in eight months in my presidency that was accomplished during the last eight years. ISIS is disappearing rapidly."
President Trump on Thursday said it would be a "very sad day" for North Korea if the U.S. military needed to use force against it.
"Military action would certainly be an option," he said during a press conference. "Nothing is inevitable. I would prefer not going the route of the military, but it could certainly happen."
"Our military is stronger now," Trump added. "Each day new and beautiful equipment is delivered, by far the best in the world. Hopefully we don't use it on North Korea. But if we do use it on North Korea, it will be a very sad day for North Korea. I will tell you that North Korea is behaving very badly and it's gotta stop."
President Trump on Thursday praised Kuwait for its contributions to defeating the Islamic State in Iraq and Syria (ISIS) and other terrorist groups.
"The United States is proud to have contributed to the liberation of Kuwait and the friendship we have built together in the years since," he said, referencing the First Gulf War from 1990 to 1991.
"We also thank Kuwait for its humanitarian leadership and its partnership in the fight to destroy ISIS," Trump added in a joint press conference with Kuwaiti leader Sabah Al Ahmad Al Sabah.
President Trump and Sheikh Sabah Al Ahmad Al Sabah, the leader of Kuwait, on Thursday are appearing together in a joint press conference after meeting in Washington, D.C.
Thursday's meeting comes as Kuwait tries mediating an ongoing diplomatic crisis between Qatar and its Arab neighbors in the Middle East.
Trump initially seemed to side with Saudi Arabia on the disagreement, but he then instructed Secretary of State Rex Tillerson to back the Kuwaiti mediation initiative.
Tillerson and other U.S. diplomats have since traveled through the region to boost Kuwait's efforts, but the dispute has dragged on despite their efforts.
Trump was also expected to discuss global efforts to isolate North Korea by halting employment of its guest workers during his talks with Al Sabah.
Kuwait has about 6,000 North Korean guest works within its borders as worldwide tensions rise over the Asian nation's pursuit of nuclear weapons.
The Associated Press contributed to this report.