Defense Secretary Leon Panetta is warning North Korea not to engage in any further provocation on the heels of the country's latest threats against South Korea.

Panetta, who is in Brazil, told reporters he had no indication of any specific actions being planned by North Korea. But he said he would "strongly urge" the North to avoid any acts that would create any greater instability in that part of the world.

Amid new concerns that North Korea may launch a second missile test, the regime said Monday it would reduce the South Korean government to "ashes." An initial missile test on April 13 failed.