North Korea leader Kim Jong Un still a mystery, Leon Panetta says WASHINGTON -- Whether North Korea's new leader will follow the dangerous path of his father is unclear, Defense Secretary Leon Panetta said on Wednesday, despite worrying behavior by the reclusive state during Kim Jong Un's first year in power. "The bottom line is we still don't know whether or not he will simply follow in the steps of his father or whether he represents a different kind of leadership for the future," Panetta said, flanked by South Korea's defense chief at a Pentagon news conference. The still largely untested Kim Jong Un, in his late 20s, has appeared to be trying hard to soften the dour image of his dictator father, whom he succeeded in December. He has appeared waving and smiling at public events, even attending a pop concert that included Disney characters. At times -- just as unusual for a North Korean leader -- he was accompanied by his wife. North Korea's leader Kim Jong-Un is married. State television made the announcement, ending weeks of speculation about the mystery woman at his side. South Korean Defense Minister Kim Kwan-jin noted that Kim Jong Un was trying to introduce economic reforms, even though he acknowledged in the same breath that it was unclear if they could succeed. But when it comes to the armed forces, the North Korean leader appears to moving ahead with the military-first policy of his father. Panetta pointed to evidence of North Korea's persistent preparations for more missile and nuclear tests and its ongoing uranium enrichment. The U.S. and South Korean defense chiefs cited North Korea's failed long-range rocket test in April. "So they continue to behave in a provocative way that threatens the security of our country and obviously of South Korea and the region," Panetta said. David Guttenfelder / AP In this March 9, 2011 photo, a girl plays the piano inside the Changgwang Elementary School in Pyongyang, North Korea. AP Photo/David Guttenfelder South Korea this month unveiled an agreement with the United States that extends the range of its ballistic missiles by more than twice the current limit to 800 km (497 miles). The agreement also increases the payload that South Korean ballistic missiles can carry. Whether the agreement acts as a deterrent remains to be seen. Panetta expressed relief that North Korea had not followed through with threats of a "merciless military strike" over efforts by activists in South Korea to launch balloons carrying propaganda leaflets across the border. US-Japan agree on new defense system to counter N. Korea missiles South Korean police banned them from sending over the leaflets but some activists reportedly moved to another site near the border and launched the balloons anyway. "I was relieved that the balloon incident, which raised concerns about potential provocation, that (it) did not occur," he said. Elizabeth Dalziel / AP From work to play, see pictures from inside the secretive country. The warning of a military strike was the most explicit in months and the first since Kim Jon Un took power. South Korea has pledged to retaliate if attacked. More than 30 years late, N. Korea's vast 'Hotel of Doom' nears completion South Korea's defense minister warned the North Korean leader may yet prove to be more aggressive. "He is still young, meaning that he may be a lot more aggressive compared to old people -- because he's still young," Kim said. The U.S. has nearly 30,000 troops on the southern side of the divided Korean Peninsula, a legacy of the 1950-53 Korean War that ended with an armistice, not a peace treaty.