Restarting a dialogue between North Korea and South Korea is an "essential first step" to returning to multinational talks on ending North Korea's nuclear program, State Department spokesman Mark Toner said on Monday.

"A successful rapprochement between North and South Korea is an essential first step before we can consider getting involved diplomatically again or even talk about six-party talks," Toner said.

Multinational talks on ending North Korea's nuclear programs have been stalled since December 2008. One month after the talks ended among the six countries -- the two Koreas, the United States, Russia, China and Japan -- North Korea launched a second nuclear test.

In March, 2010, North Korea was accused of sinking the South Korean navy ship, the Cheonan, and later that year, the bombardment of the South Korean island of Yeonpyeong.

"We've seen a steady pattern of belligerent behavior on the part of North Korea," noted Toner.

"So we need to see a clear and decisive move in the opposite direction. ... The other side of this coin is a pattern where we reward bad behavior on the part of North Korea and we hold talks that don't lead anywhere," Toner added. "And we've said very consistently that we're not going to have talks for talks' sake."