WASHINGTON (Yonhap News) -- U.S. Secretary of State John Kerry had a "productive exchange" with a visiting top South Korean presidential aide Friday on North Korea and other pending issues, the department said.

Wendy Sherman, undersecretary of state for political affairs, joined the meeting between Kerry and Kim Jang-soo, chief of Cheong Wa Dae's national security office, according to department spokeswoman Jen Psaki.

"Both sides reaffirmed our intention to coordinate and closely cooperate with respect to our policy approach to North Korea," she said at a press briefing.

Asked about the possibility of resuming dialogue with the North, Psaki stressed it's up to the communist nation.

"Our position hasn't changed, but the ball is in North Korea's court, so nothing has changed on that front as of this morning," she said.

The Obama administration is demanding North Korea prove its seriousness on talks through actions, not rhetoric.

Kim, formerly South Korea's defense minister, arrived here Wednesday for a four-day stay, his first trip to the U.S. since becoming the chief national security assistant to President Park Geun-hye in February.

He met with Secretary of State Chuck Hagel later Friday.