Negotiators from South and North Korea resumed high-level talks Sunday afternoon to avoid an "all-out war" on the Korean peninsula.

The top-level talks, a first in years, began Saturday in the historic "truce village" of Panmunjom near a highly fortified border between rival nations, reported BBC News. Negotiators from both countries agreed to a second round of talks after Saturday's marathon night-long negotiations failed to resolve the crisis.

South Korean National Security Adviser Kim Kwan-Jin and Unification Minister Hong Yong-Pyo are holding talks with North Korean military's top political officer Hwang Pyong-so and Kim Yang-gon, the official in charge of inter-Korean affairs, in a closed door meeting at Panmunjom, according to Korea Times.

A senior South Korean officer, however, said that North Korea is gearing for a possible attack. "More than 50 North Korean submarines are apparently away from their bases for operations, a sign that the North is gearing up for combat while participating in high-level talks aimed at easing tension," the military official said on Sunday, according to Yonhap news agency.

"Seventy percent of North Korea's submarines left their bases, and their locations are not confirmed," the official said.

North Korea warned Saturday it is ready to go into an "all out war" with South Korea to defend itself.

"Our military and people are prepared to risk an all-out war not just to simply respond or retaliate, but to defend the system our people chose. The situation has reached the verge of war and can no longer be reversed," the North Korean foreign ministry said in a statement on Saturday, as previously reported by HNGN.