YEONPYEONG ISLAND, South Korea – North Korea backed off threats to retaliate against South Korea for military drills Monday and reportedly offered concessions on its nuclear program — signs it was looking to lower the temperature on the Korean peninsula after weeks of soaring tensions.

But Pyongyang has feinted toward conciliation before and failed to follow through.

The North's gestures came after South Korea launched fighter jets, evacuated hundreds of residents near its tense land border with the North and sent residents of islands near disputed waters into underground bunkers in case Pyongyang followed through on its vow to attack over the drills...