After the highest-level UN trip to N Korea in six years, the senior official said there was an “urgent need” to keep channels with the isolated nation to avoid the risk of war.
UN said North has agreed to regular communications from now.
Tensions over the North’s weapons program were raised after fresh ballistic missile test last week.
North said the missile tested was capable of reaching the US mainland.
The test was the latest in a series of nuclear and missile tests conducted in defiance of US sanctions.