WASHINGTON - North Korea must commit to dismantling its nuclear weapons program, new U.S. Secretary of State Mike Pompeo said on Wednesday during a swearing-in ceremony at the State Department where he was strongly endorsed by U.S. President Donald Trump.It was Trump's first visit to the State Department, where he was greeted by loud applause from several hundred people gathered in the Benjamin Franklin state dining room."That's more spirit than I've heard from the State Department in a long time," Trump joked, praising Pompeo's credentials and record as CIA director.Trump fired his first secretary of state, Rex Tillerson, in March after public disagreements over North Korea, Iran and Russia. The department had been sidelined on major foreign policy issues and shaken by the resignation of senior diplomats."I have no doubt that you will make America proud as our nation's chief diplomat," Trump told Pompeo before Vice President Mike Pence administered the oath in a ceremonial swearing in.Pompeo, who secretly met with North Korean leader Kim Jong Un over the Easter weekend, said North Korea must commit to immediately dismantling its weapons program, adding that efforts to denuclearize Pyongyang were still in the "beginning stages" and the outcomes "unknown." "We are committed to the permanent, verifiable, irreversible dismantling of North Korea's weapons of mass destruction program and to do so without delay," he said as Trump prepares for a historic meeting with Kim to convince Pyongyang to abandon its nuclear missile program.In a statement later marking North Korea Freedom Week, the State Department said it was gravely concerned about human rights abuses by what it called one of the most repressive and abusive governments in the world."We remain gravely concerned and deeply troubled by these abuses," the department said. "In tandem with the maximum pressure campaign, we will continue to press for accountability for those responsible." Listing major challenges ahead, Pompeo said the United States was deciding on next steps of a "flawed" nuclear deal with Iran and confronting Moscow's "acts of aggression." "My team and I will be unrelenting in confronting those threats," said Pompeo. "We will deploy tough diplomacy when necessary to put the interest of the American people first," he added.Pompeo sought to quickly put his mark on his new role as secretary of state by rushing off to meet allies in Europe and the Middle East moments after he was confirmed on Thursday.In his talks with NATO foreign ministers in Brussels, Pompeo emphasized Russian aggression and pushed for higher defense spending.In the Middle East, he warned of Iran's "malign behavior" as he discussed changes to the 2015 Iran nuclear deal.He stressed that the United States had not decided whether to withdraw from the deal struck with Iran and six major powers including France, Germany, Britain, Russia and China.