U.S. Secretary of State Rex Tillerson speaks during a news conference in Bogota, Colombia February 6, 2018. REUTERS/Jaime Saldarriaga

CAIRO (Reuters) - U.S. Secretary of State Rex Tillerson said in Cairo on Monday it was up to North Korea to decide when it was ready to engage in sincere talks with the United States.

U.S. Vice President Mike Pence said in a newspaper interview that Washington and Seoul had agreed on terms for further diplomatic engagement with North Korea, possibly leading to direct talks without pre-conditions.

Tillerson told a news conference it was too early to judge whether this was the start of a diplomatic process.