Judy Woodruff:

In the day's other news: Russia's President Vladimir Putin and Ukraine's President Volodymyr Zelensky held their first one-on-one meeting. It came in Paris, after they met with French President Emmanuel Macron and Germany's Chancellor Angela Merkel for broader talks at a peace summit.

Putin and Zelensky said the meetings were positive, and they agreed on a prisoner swap. Russia backs rebel forces that control Eastern Ukraine.

North Korea sent hostile new words in the direction of President Trump today. Former nuclear negotiator Kim Yong-chol called the president — quote — "a heedless and erratic old man."

That came after Mr. Trump tweeted Sunday that North Korea's leader, Kim Jong-un, is — quote — "too smart" and has gone too far — and has far too much to lose to return to open hostility.

Iran says that it is ready to swap more prisoners with the U.S. after an exchange on Saturday. Tehran freed a Chinese-American scholar who is accused of espionage. Washington released an Iranian scientist charged with violating sanctions on Iran.

In Tehran today, a government spokesman said the swap doesn't open the door to broader talks.