South Korea's chief nuclear envoy, Noh Kyu-duk, held phone talks with his Japanese counterpart, Takehiro Funakoshi, on Monday to discuss cooperation to foster lasting peace on the Korean Peninsula, the foreign ministry said.

The talks came after last week's restoration of inter-Korean communication lines raised hopes for the resumption of nuclear diplomacy with Pyongyang, though Kim Yo-jong, the sister of North Korean leader Kim Jong-un, warned Sunday the planned summertime military drills between the South and the United States will cloud the future of cross-border relations.

"The two sides shared assessments of recent Korean Peninsula situations, including the restoration of inter-Korean communication lines," the ministry said in a press release.

"They exchanged opinions on ways to cooperate between the South and Japan, and among the South, the US and Japan for substantive progress in the efforts for the complete denuclearization of the peninsula and the establishment of lasting peace," it added.

The two Koreas reactivated communication lines on Tuesday, 13 months after the reclusive regime unilaterally severed them in anger over South Korean activists sending anti-Pyongyang leaflets across the border.

Since then, Seoul has been cranking up diplomacy with the US and other concerned countries to advance its drive to build peace with the North. On Thursday, Noh held phone talks with his US counterpart, Sung Kim. (Yonhap)