NEWTON, Mass. — Former U.N. Secretary-General Ban Ki-moon is making an appearance at Boston College.

Ban was South Korea's foreign minister before serving 10 years as U.N. chief. He's scheduled to speak Tuesday on "human welfare and global citizenship."

Ban told the U.N. Security Council last week that the "current reconciliatory atmosphere" between North and South Korea that began during the 2018 Winter Olympics must be kept alive. He called on the U.S. to play a role by engaging with North Korea.

At Brown University in Providence, Rhode Island, on Monday, Ban expressed optimism about recent dialogue between North and South Korea and added that another war in the region is "unacceptable and unthinkable."

He said President Donald Trump has been sending a "loud and clear message" to North Korea.